Fix CI: useless cast in the Zmij digit writer and snprintf truncation

- ci_test_gcc (Linux x86-64): static_cast<std::size_t>(d.significand % 100) was a useless cast (a std::uint64_t prvalue, the same type as std::size_t there); cast a named variable instead. - ci_test_gcc: -Werror=format-truncation for snprintf("%.*e") in unit-to_chars.cpp, whose precision GCC cannot bound; write the neighboring decimal with a stream (classic locale, std::scientific), which gives the same text. Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Write doubles with the shortest digits (Zmij)
2026-09-30 19:50:34 +00:00 · 2026-09-30 21:02:19 +02:00 · 2026-09-30 21:02:18 +02:00 · 2026-09-30 21:02:17 +02:00 · 2026-09-30 21:02:16 +02:00 · 2026-09-30 21:02:15 +02:00
367 changed files with 38486 additions and 1769 deletions
@@ -45,6 +45,24 @@ labels:
 - label: "aspect: binary formats"
  title: "(?i)(bson|cbor|msgpack|messagepack|ubjson|bjdata|bon8|binary format)"

+- label: "aspect: json_view"
+  files:
+    - "include/nlohmann/json_view\\.hpp"
+    - "include/nlohmann/detail/view/.*"
+    - "single_include/nlohmann/json_view\\.hpp"
+    - "tests/src/unit-json_view.*"
+    - "tests/src/fuzzer-(parse_json_view|json_view_image)\\.cpp"
+    - "tests/benchmarks/json_view/.*"
+    - "tools/amalgamate/config_json_view\\.json"
+    - "docs/mkdocs/docs/features/json_view\\.md"
+    - "docs/mkdocs/docs/api/basic_json_(document|view)/.*"
+    - "docs/mkdocs/docs/api/(ordered_)?json_(editable_)?(document|view)\\.md"
+    - "docs/mkdocs/docs/examples/(basic_json_(document|view)__|(ordered_)?json_(editable_)?(document|view)).*"
+    - "tests/benchmarks/src/benchmarks_view\\.cpp"
+
+- label: "aspect: json_view"
+  title: "(?i)(json_view|json_document|zero-copy)"
+
 - label: "python"
  files:
    - "\\.py$"
@@ -67,12 +67,16 @@ jobs:

          python3 $TOOL_DIR/amalgamate.py -c $TOOL_DIR/config_json.json -s .
          python3 $TOOL_DIR/amalgamate.py -c $TOOL_DIR/config_json_fwd.json -s .
+          cp include/nlohmann/json_literals.hpp $INCLUDE_DIR/json_literals.hpp
+          # the configuration of json_view.hpp comes with the pull request until
+          # it is on develop; the tool itself is still develop's
+          python3 $TOOL_DIR/amalgamate.py -c $MAIN_DIR/tools/amalgamate/config_json_view.json -s .

          # the header list of the Bazel "json" target must match the files in include/
          cmake -P cmake/scripts/gen_bazel_build_file.cmake

          ${{ github.workspace }}/venv/bin/astyle --project=tools/astyle/.astylerc --suffix=none --quiet \
-            $INCLUDE_DIR/json.hpp $INCLUDE_DIR/json_fwd.hpp
+            $INCLUDE_DIR/json.hpp $INCLUDE_DIR/json_fwd.hpp $INCLUDE_DIR/json_view.hpp

          # fail loudly if a directory is renamed or removed: find would only warn
          # about the missing path and silently drop its files from the check
@@ -0,0 +1,78 @@
+name: "json_view benchmarks"
+
+# On demand only: runs the comparison of json_view with yyjson, simdjson, and
+# Boost.JSON (tests/benchmarks/json_view/compare.py) on GitHub-hosted runners,
+# for numbers from x86-64 and AArch64 Linux. It runs when started by hand, or
+# when a pull request gets the label "benchmark" (on both architectures, with
+# GCC and the default settings). Shared runners are noisy: the results show
+# where json_view stands, but published numbers need a quiet machine (see
+# tests/benchmarks/json_view/README.md).
+
+on:
+  pull_request:
+    types: [labeled]
+  workflow_dispatch:
+    inputs:
+      runner:
+        description: "Runner image"
+        type: choice
+        options:
+          - ubuntu-24.04
+          - ubuntu-24.04-arm
+        default: ubuntu-24.04
+      compiler:
+        description: "Compiler"
+        type: choice
+        options:
+          - g++
+          - clang++
+        default: g++
+      native:
+        description: "Compile for the runner's CPU (-march=native)"
+        type: boolean
+        default: false
+      rounds:
+        description: "Rounds of bench_view"
+        type: number
+        default: 30
+
+permissions:
+  contents: read
+
+jobs:
+  compare:
+    if: github.event_name == 'workflow_dispatch' || github.event.label.name == 'benchmark'
+    strategy:
+      matrix:
+        runner: ${{ fromJSON(github.event_name == 'workflow_dispatch' && format('["{0}"]', inputs.runner) || '["ubuntu-24.04", "ubuntu-24.04-arm"]') }}
+    runs-on: ${{ matrix.runner }}
+    steps:
+      - name: Harden Runner
+        uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
+        with:
+          egress-policy: audit
+
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
+
+      - name: Download test data
+        run: |
+          cmake -S . -B build -DJSON_BuildTests=On
+          cmake --build build --target download_test_data
+
+      - name: Run the comparison
+        env:
+          CXX: ${{ inputs.compiler || 'g++' }}
+          CC: ${{ inputs.compiler == 'clang++' && 'clang' || 'gcc' }}
+          ROUNDS: ${{ inputs.rounds || 30 }}
+          NATIVE: ${{ inputs.native && '--native' || '' }}
+        run: python3 tests/benchmarks/json_view/compare.py --data build/test_files --download --rounds "$ROUNDS" $NATIVE
+
+      - name: Summary
+        run: cat tests/benchmarks/json_view/results/*.md >> "$GITHUB_STEP_SUMMARY"
+
+      - uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
+        with:
+          name: json_view-benchmarks-${{ matrix.runner }}-${{ inputs.compiler || 'g++' }}
+          path: tests/benchmarks/json_view/results/
@@ -20,10 +20,13 @@ cc_library(
    hdrs = [
        "include/nlohmann/adl_serializer.hpp",
        "include/nlohmann/byte_container_with_subtype.hpp",
+        "include/nlohmann/detail/abi_config.hpp",
        "include/nlohmann/detail/abi_macros.hpp",
+        "include/nlohmann/detail/bit_ops.hpp",
        "include/nlohmann/detail/conversions/from_json.hpp",
        "include/nlohmann/detail/conversions/to_chars.hpp",
        "include/nlohmann/detail/conversions/to_json.hpp",
+        "include/nlohmann/detail/conversions/zmij.hpp",
        "include/nlohmann/detail/exceptions.hpp",
        "include/nlohmann/detail/hash.hpp",
        "include/nlohmann/detail/input/binary_reader.hpp",
@@ -33,6 +36,7 @@ cc_library(
        "include/nlohmann/detail/input/number_parse.hpp",
        "include/nlohmann/detail/input/parser.hpp",
        "include/nlohmann/detail/input/position_t.hpp",
+        "include/nlohmann/detail/input/pow5_table.hpp",
        "include/nlohmann/detail/input/string_scan.hpp",
        "include/nlohmann/detail/iterators/internal_iterator.hpp",
        "include/nlohmann/detail/iterators/iter_impl.hpp",
@@ -63,8 +67,32 @@ cc_library(
        "include/nlohmann/detail/string_escape.hpp",
        "include/nlohmann/detail/string_utils.hpp",
        "include/nlohmann/detail/value_t.hpp",
+        "include/nlohmann/detail/view/builder.hpp",
+        "include/nlohmann/detail/view/compare.hpp",
+        "include/nlohmann/detail/view/document_data.hpp",
+        "include/nlohmann/detail/view/edit.hpp",
+        "include/nlohmann/detail/view/edit_storage.hpp",
+        "include/nlohmann/detail/view/errors.hpp",
+        "include/nlohmann/detail/view/image.hpp",
+        "include/nlohmann/detail/view/input.hpp",
+        "include/nlohmann/detail/view/iterator.hpp",
+        "include/nlohmann/detail/view/lookup.hpp",
+        "include/nlohmann/detail/view/macro_scope.hpp",
+        "include/nlohmann/detail/view/macro_unscope.hpp",
+        "include/nlohmann/detail/view/materialize.hpp",
+        "include/nlohmann/detail/view/node.hpp",
+        "include/nlohmann/detail/view/number.hpp",
+        "include/nlohmann/detail/view/object_index.hpp",
+        "include/nlohmann/detail/view/pointer.hpp",
+        "include/nlohmann/detail/view/scan.hpp",
+        "include/nlohmann/detail/view/serializer.hpp",
+        "include/nlohmann/detail/view/simd.hpp",
+        "include/nlohmann/detail/view/string_ref.hpp",
+        "include/nlohmann/detail/view/value.hpp",
        "include/nlohmann/json.hpp",
        "include/nlohmann/json_fwd.hpp",
+        "include/nlohmann/json_literals.hpp",
+        "include/nlohmann/json_view.hpp",
        "include/nlohmann/ordered_map.hpp",
        "include/nlohmann/thirdparty/hedley/hedley.hpp",
        "include/nlohmann/thirdparty/hedley/hedley_undef.hpp",
@@ -77,6 +105,7 @@ cc_library(
    name = "singleheader-json",
    hdrs = [
        "single_include/nlohmann/json.hpp",
+        "single_include/nlohmann/json_view.hpp",
    ],
    includes = ["single_include"],
    visibility = ["//visibility:public"],
@@ -21,6 +21,9 @@ TESTS_SRCS=$(shell find tests -type f \( -name '*.hpp' -o -name '*.cpp' -o -name
 # the single headers (amalgamated from the source files)
 AMALGAMATED_FILE=single_include/nlohmann/json.hpp
 AMALGAMATED_FWD_FILE=single_include/nlohmann/json_fwd.hpp
+# json_literals.hpp only includes <nlohmann/json.hpp>, so it is copied verbatim
+AMALGAMATED_LITERALS_FILE=single_include/nlohmann/json_literals.hpp
+AMALGAMATED_VIEW_FILE=single_include/nlohmann/json_view.hpp


 ##########################################################################
@@ -29,7 +32,7 @@ AMALGAMATED_FWD_FILE=single_include/nlohmann/json_fwd.hpp

 # main target
 all:
-	@echo "amalgamate - amalgamate files single_include/nlohmann/json{,_fwd}.hpp from the include/nlohmann sources"
+	@echo "amalgamate - amalgamate files single_include/nlohmann/json{,_fwd,_literals,_view}.hpp from the include/nlohmann sources"
 	@echo "BUILD.bazel - regenerate the Bazel BUILD file from the include/nlohmann sources"
 	@echo "ChangeLog.md - generate ChangeLog file"
 	@echo "check-amalgamation - check whether sources have been amalgamated and BUILD.bazel is up to date"
@@ -39,6 +42,7 @@ all:
 	@echo "fuzz_testing_bon8 - prepare fuzz testing of the BON8 parser"
 	@echo "fuzz_testing_bson - prepare fuzz testing of the BSON parser"
 	@echo "fuzz_testing_cbor - prepare fuzz testing of the CBOR parser"
+	@echo "fuzz_testing_json_view - prepare fuzz testing of the json_document/json_view parser"
 	@echo "fuzz_testing_msgpack - prepare fuzz testing of the MessagePack parser"
 	@echo "fuzz_testing_ubjson - prepare fuzz testing of the UBJSON parser"
 	@echo "pretty - beautify code with Artistic Style"
@@ -96,6 +100,14 @@ fuzz_testing_cbor:
 	find tests/data -size -5k -name *.cbor | xargs -I{} cp "{}" fuzz-testing/testcases
 	@echo "Execute: afl-fuzz -i fuzz-testing/testcases -o fuzz-testing/out fuzz-testing/fuzzer"

+fuzz_testing_json_view:
+	rm -fr fuzz-testing
+	mkdir -p fuzz-testing fuzz-testing/testcases fuzz-testing/out
+	$(MAKE) parse_json_view_fuzzer -C tests CXX=afl-clang++
+	mv tests/parse_json_view_fuzzer fuzz-testing/fuzzer
+	find tests/data/json_tests -size -5k -name *json | xargs -I{} cp "{}" fuzz-testing/testcases
+	@echo "Execute: afl-fuzz -i fuzz-testing/testcases -o fuzz-testing/out fuzz-testing/fuzzer"
+
 fuzz_testing_msgpack:
 	rm -fr fuzz-testing
 	mkdir -p fuzz-testing fuzz-testing/testcases fuzz-testing/out
@@ -154,14 +166,14 @@ install_astyle:

 # call the Artistic Style pretty printer on all source files
 pretty: install_astyle
-	$(ASTYLE) --project=tools/astyle/.astylerc $(SRCS) $(TESTS_SRCS) $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) docs/mkdocs/docs/examples/*.cpp
+	$(ASTYLE) --project=tools/astyle/.astylerc $(SRCS) $(TESTS_SRCS) $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_LITERALS_FILE) $(AMALGAMATED_VIEW_FILE) docs/mkdocs/docs/examples/*.cpp

 # call the Clang-Format on all source files
 pretty_format:
 	for FILE in $(SRCS) $(TESTS_SRCS) $(AMALGAMATED_FILE) docs/mkdocs/docs/examples/*.cpp; do echo $$FILE; clang-format -i $$FILE; done

 # create single header files and pretty print
-amalgamate: $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE)
+amalgamate: $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_LITERALS_FILE) $(AMALGAMATED_VIEW_FILE)
 	$(MAKE) pretty

 # call the amalgamation tool for json.hpp
@@ -172,16 +184,30 @@ $(AMALGAMATED_FILE): $(SRCS)
 $(AMALGAMATED_FWD_FILE): $(SRCS)
 	tools/amalgamate/amalgamate.py -c tools/amalgamate/config_json_fwd.json -s . --verbose=yes

+# copy json_literals.hpp
+$(AMALGAMATED_LITERALS_FILE): include/nlohmann/json_literals.hpp
+	cp include/nlohmann/json_literals.hpp $(AMALGAMATED_LITERALS_FILE)
+
+# call the amalgamation tool for json_view.hpp (keeps including json.hpp)
+$(AMALGAMATED_VIEW_FILE): $(SRCS)
+	tools/amalgamate/amalgamate.py -c tools/amalgamate/config_json_view.json -s . --verbose=yes
+
 # check if file single_include/nlohmann/json.hpp has been amalgamated from the nlohmann sources
 # Note: this target is called by Travis
 check-amalgamation:
 	@mv $(AMALGAMATED_FILE) $(AMALGAMATED_FILE)~
 	@mv $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_FWD_FILE)~
+	@mv $(AMALGAMATED_LITERALS_FILE) $(AMALGAMATED_LITERALS_FILE)~
+	@mv $(AMALGAMATED_VIEW_FILE) $(AMALGAMATED_VIEW_FILE)~
 	@$(MAKE) amalgamate
 	@diff $(AMALGAMATED_FILE) $(AMALGAMATED_FILE)~ || (echo "===================================================================\n  Amalgamation required! Please read the contribution guidelines\n  in file .github/CONTRIBUTING.md.\n===================================================================" ; mv $(AMALGAMATED_FILE)~ $(AMALGAMATED_FILE) ; false)
 	@diff $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_FWD_FILE)~ || (echo "===================================================================\n  Amalgamation required! Please read the contribution guidelines\n  in file .github/CONTRIBUTING.md.\n===================================================================" ; mv $(AMALGAMATED_FWD_FILE)~ $(AMALGAMATED_FWD_FILE) ; false)
+	@diff $(AMALGAMATED_LITERALS_FILE) $(AMALGAMATED_LITERALS_FILE)~ || (echo "===================================================================\n  Amalgamation required! Please read the contribution guidelines\n  in file .github/CONTRIBUTING.md.\n===================================================================" ; mv $(AMALGAMATED_LITERALS_FILE)~ $(AMALGAMATED_LITERALS_FILE) ; false)
+	@diff $(AMALGAMATED_VIEW_FILE) $(AMALGAMATED_VIEW_FILE)~ || (echo "===================================================================\n  Amalgamation required! Please read the contribution guidelines\n  in file .github/CONTRIBUTING.md.\n===================================================================" ; mv $(AMALGAMATED_VIEW_FILE)~ $(AMALGAMATED_VIEW_FILE) ; false)
 	@mv $(AMALGAMATED_FILE)~ $(AMALGAMATED_FILE)
 	@mv $(AMALGAMATED_FWD_FILE)~ $(AMALGAMATED_FWD_FILE)
+	@mv $(AMALGAMATED_LITERALS_FILE)~ $(AMALGAMATED_LITERALS_FILE)
+	@mv $(AMALGAMATED_VIEW_FILE)~ $(AMALGAMATED_VIEW_FILE)
 	@mv BUILD.bazel BUILD.bazel~
 	@$(MAKE) BUILD.bazel
 	@diff BUILD.bazel BUILD.bazel~ || (echo "===================================================================\n  BUILD.bazel is out of date! Please run 'make BUILD.bazel'.\n===================================================================" ; mv BUILD.bazel~ BUILD.bazel ; false)
@@ -222,7 +248,7 @@ json.tar.xz:
 # We use `-X` to make the resulting ZIP file reproducible, see
 # <https://content.pivotal.io/blog/barriers-to-deterministic-reproducible-zip-files>.
 include.zip: BUILD.bazel
-	zip -9 --recurse-paths -X include.zip $(SRCS) $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) BUILD.bazel MODULE.bazel meson.build LICENSE.MIT
+	zip -9 --recurse-paths -X include.zip $(SRCS) $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_LITERALS_FILE) $(AMALGAMATED_VIEW_FILE) BUILD.bazel MODULE.bazel meson.build LICENSE.MIT

 # Create the files for a release and add signatures and hashes.
 release: include.zip json.tar.xz
@@ -231,11 +257,15 @@ release: include.zip json.tar.xz
 	gpg --armor --detach-sig include.zip
 	gpg --armor --detach-sig $(AMALGAMATED_FILE)
 	gpg --armor --detach-sig $(AMALGAMATED_FWD_FILE)
+	gpg --armor --detach-sig $(AMALGAMATED_LITERALS_FILE)
+	gpg --armor --detach-sig $(AMALGAMATED_VIEW_FILE)
 	gpg --armor --detach-sig json.tar.xz
 	cp $(AMALGAMATED_FILE) release_files
 	cp $(AMALGAMATED_FWD_FILE) release_files
-	mv $(AMALGAMATED_FILE).asc $(AMALGAMATED_FWD_FILE).asc json.tar.xz json.tar.xz.asc include.zip include.zip.asc release_files
-	cd release_files ; shasum -a 256 json.hpp include.zip json.tar.xz > hashes.txt
+	cp $(AMALGAMATED_LITERALS_FILE) release_files
+	cp $(AMALGAMATED_VIEW_FILE) release_files
+	mv $(AMALGAMATED_FILE).asc $(AMALGAMATED_FWD_FILE).asc $(AMALGAMATED_LITERALS_FILE).asc $(AMALGAMATED_VIEW_FILE).asc json.tar.xz json.tar.xz.asc include.zip include.zip.asc release_files
+	cd release_files ; shasum -a 256 json.hpp json_view.hpp include.zip json.tar.xz > hashes.txt


 ##########################################################################
@@ -1189,6 +1189,14 @@ binary.set_subtype(0x10);
 auto cbor = json::to_msgpack(j); // 0xD5 (fixext2), 0x10, 0xCA, 0xFE
 ```

+### Zero-copy views
+
+Header `<nlohmann/json_view.hpp>` adds `json_document`/`json_view`, a read-only, non-owning way to look at a parsed
+JSON text: parsing builds a flat index (16 bytes per value) instead of a tree, strings and numbers stay in the source
+text, and `materialize()` builds a `json` value for a subtree only when you actually need one. See
+[Zero-copy JSON views](https://json.nlohmann.me/features/json_view/) for the details, including which inputs are
+borrowed and which are copied.
+
 ## Customers

 The library is used in multiple projects, applications, operating systems, etc. The list below is not exhaustive, but the result of an internet search. If you know further customers of the library, please let me know, see [contact](#contact).
@@ -1393,8 +1401,12 @@ THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR I

 - The class contains the UTF-8 Decoder from Bjoern Hoehrmann which is licensed under the [MIT License](https://opensource.org/licenses/MIT) (see above). Copyright &copy; 2008-2009 [Björn Hoehrmann](https://bjoern.hoehrmann.de/) <bjoern@hoehrmann.de>
 - The class contains a slightly modified version of the Grisu2 algorithm from Florian Loitsch which is licensed under the [MIT License](https://opensource.org/licenses/MIT) (see above). Copyright &copy; 2009 [Florian Loitsch](https://florian.loitsch.com/)
+- The class contains a port of the shortest double-to-decimal conversion of [Żmij](https://github.com/vitaut/zmij) by Victor Zverovich, which is licensed under the [MIT License](https://opensource.org/licenses/MIT) (see above). Copyright &copy; 2025 [Victor Zverovich](https://github.com/vitaut)
 - The class contains a copy of [Hedley](https://nemequ.github.io/hedley/) from Evan Nemerson which is licensed as [CC0-1.0](https://creativecommons.org/publicdomain/zero/1.0/).
 - The class contains parts of [Google Abseil](https://github.com/abseil/abseil-cpp) which is licensed under the [Apache 2.0 License](https://opensource.org/licenses/Apache-2.0).
+- The class contains an adapted version of the Eisel-Lemire algorithm, its table of powers of five, and its digit comparison for long numbers from [fast_float](https://github.com/fastfloat/fast_float) by Daniel Lemire and contributors, which is available under the [MIT License](https://opensource.org/licenses/MIT) (used here), the Apache 2.0 License, and the Boost Software License. Copyright &copy; 2021 The fast_float authors
+- The view's parser (`<nlohmann/json_view.hpp>`) contains techniques and code adapted from [yyjson](https://github.com/ibireme/yyjson) by YaoYuan, which is licensed under the [MIT License](https://opensource.org/licenses/MIT) (see above): table-driven decoding of `\u` escapes and fixed-offset unrolled checks.
+- The view's parser (`<nlohmann/json_view.hpp>`) validates non-ASCII strings with the vector UTF-8 check of [simdjson](https://github.com/simdjson/simdjson) by Daniel Lemire, Geoff Langdale, John Keiser, and contributors (its "lookup4" algorithm and tables, after J. Keiser and D. Lemire, "Validating UTF-8 In Less Than One Instruction Per Byte", 2021), which is available under the [MIT License](https://opensource.org/licenses/MIT) (used here) and the Apache 2.0 License. Copyright &copy; 2018-2025 The simdjson authors

 <img align="right" src="https://git.fsfe.org/reuse/reuse-ci/raw/branch/master/reuse-horizontal.png" alt="REUSE Software">

@@ -373,9 +373,11 @@ file(GLOB_RECURSE INDENT_FILES
 set(include_dir ${PROJECT_SOURCE_DIR}/single_include/nlohmann)
 set(tool_dir ${PROJECT_SOURCE_DIR}/tools/amalgamate)
 add_custom_target(ci_test_amalgamation
-    COMMAND rm -fr ${include_dir}/json.hpp~ ${include_dir}/json_fwd.hpp~
+    COMMAND rm -fr ${include_dir}/json.hpp~ ${include_dir}/json_fwd.hpp~ ${include_dir}/json_literals.hpp~ ${include_dir}/json_view.hpp~
    COMMAND cp ${include_dir}/json.hpp ${include_dir}/json.hpp~
    COMMAND cp ${include_dir}/json_fwd.hpp ${include_dir}/json_fwd.hpp~
+    COMMAND cp ${include_dir}/json_literals.hpp ${include_dir}/json_literals.hpp~
+    COMMAND cp ${include_dir}/json_view.hpp ${include_dir}/json_view.hpp~

    COMMAND ${Python3_EXECUTABLE} -mvenv venv_astyle
    COMMAND venv_astyle/bin/pip3 --quiet install -r ${CMAKE_SOURCE_DIR}/tools/astyle/requirements.txt
@@ -383,10 +385,14 @@ add_custom_target(ci_test_amalgamation

    COMMAND ${Python3_EXECUTABLE} ${tool_dir}/amalgamate.py -c ${tool_dir}/config_json.json -s .
    COMMAND ${Python3_EXECUTABLE} ${tool_dir}/amalgamate.py -c ${tool_dir}/config_json_fwd.json -s .
-    COMMAND venv_astyle/bin/astyle --project=tools/astyle/.astylerc --suffix=none ${include_dir}/json.hpp ${include_dir}/json_fwd.hpp
+    COMMAND cp ${PROJECT_SOURCE_DIR}/include/nlohmann/json_literals.hpp ${include_dir}/json_literals.hpp
+    COMMAND ${Python3_EXECUTABLE} ${tool_dir}/amalgamate.py -c ${tool_dir}/config_json_view.json -s .
+    COMMAND venv_astyle/bin/astyle --project=tools/astyle/.astylerc --suffix=none ${include_dir}/json.hpp ${include_dir}/json_fwd.hpp ${include_dir}/json_view.hpp

    COMMAND diff ${include_dir}/json.hpp~ ${include_dir}/json.hpp
    COMMAND diff ${include_dir}/json_fwd.hpp~ ${include_dir}/json_fwd.hpp
+    COMMAND diff ${include_dir}/json_literals.hpp~ ${include_dir}/json_literals.hpp
+    COMMAND diff ${include_dir}/json_view.hpp~ ${include_dir}/json_view.hpp

    COMMAND venv_astyle/bin/astyle --project=tools/astyle/.astylerc --suffix=orig ${INDENT_FILES}
    COMMAND for FILE in `find . -name '*.orig'`\; do false \; done
@@ -48,6 +48,7 @@ cc_library(
    name = "singleheader-json",
    hdrs = [
        "single_include/nlohmann/json.hpp",
+        "single_include/nlohmann/json_view.hpp",
    ],
    includes = ["single_include"],
    visibility = ["//visibility:public"],
@@ -128,7 +128,74 @@ INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::to_ubjson', 'Func
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::value', 'Method', 'api/basic_json/value/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::value_t', 'Enum', 'api/basic_json/value_t/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::~basic_json', 'Method', 'api/basic_json/~basic_json/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document', 'Class', 'api/basic_json_document/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::basic_json_document', 'Constructor', 'api/basic_json_document/basic_json_document/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::accept', 'Function', 'api/basic_json_document/accept/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::erase', 'Method', 'api/basic_json_document/erase/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::insert', 'Method', 'api/basic_json_document/insert/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::is_discarded', 'Method', 'api/basic_json_document/is_discarded/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::load', 'Function', 'api/basic_json_document/load/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::memory_usage', 'Method', 'api/basic_json_document/memory_usage/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::node_count', 'Method', 'api/basic_json_document/node_count/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::owns_source', 'Method', 'api/basic_json_document/owns_source/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::parse', 'Function', 'api/basic_json_document/parse/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::parse_copy', 'Function', 'api/basic_json_document/parse_copy/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::push_back', 'Method', 'api/basic_json_document/push_back/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::read', 'Method', 'api/basic_json_document/read/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::root', 'Method', 'api/basic_json_document/root/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::save', 'Method', 'api/basic_json_document/save/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::set', 'Method', 'api/basic_json_document/set/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::shrink_to_fit', 'Method', 'api/basic_json_document/shrink_to_fit/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::source', 'Method', 'api/basic_json_document/source/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view', 'Class', 'api/basic_json_view/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::basic_json_view', 'Constructor', 'api/basic_json_view/basic_json_view/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::at', 'Method', 'api/basic_json_view/at/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::back', 'Method', 'api/basic_json_view/back/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::begin', 'Method', 'api/basic_json_view/begin/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::cbegin', 'Method', 'api/basic_json_view/cbegin/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::cend', 'Method', 'api/basic_json_view/cend/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::contains', 'Method', 'api/basic_json_view/contains/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::count', 'Method', 'api/basic_json_view/count/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::dump', 'Method', 'api/basic_json_view/dump/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::empty', 'Method', 'api/basic_json_view/empty/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::end', 'Method', 'api/basic_json_view/end/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::find', 'Method', 'api/basic_json_view/find/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::front', 'Method', 'api/basic_json_view/front/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::get', 'Method', 'api/basic_json_view/get/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::get_string', 'Method', 'api/basic_json_view/get_string/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::get_to', 'Method', 'api/basic_json_view/get_to/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_array', 'Method', 'api/basic_json_view/is_array/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_binary', 'Method', 'api/basic_json_view/is_binary/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_boolean', 'Method', 'api/basic_json_view/is_boolean/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_discarded', 'Method', 'api/basic_json_view/is_discarded/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_null', 'Method', 'api/basic_json_view/is_null/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_number', 'Method', 'api/basic_json_view/is_number/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_number_float', 'Method', 'api/basic_json_view/is_number_float/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_number_integer', 'Method', 'api/basic_json_view/is_number_integer/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_number_unsigned', 'Method', 'api/basic_json_view/is_number_unsigned/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_object', 'Method', 'api/basic_json_view/is_object/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_primitive', 'Method', 'api/basic_json_view/is_primitive/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_string', 'Method', 'api/basic_json_view/is_string/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_structured', 'Method', 'api/basic_json_view/is_structured/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::items', 'Method', 'api/basic_json_view/items/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::materialize', 'Method', 'api/basic_json_view/materialize/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::number_format', 'Enum', 'api/basic_json_view/number_format/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::number_token', 'Method', 'api/basic_json_view/number_token/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::operator bool', 'Method', 'api/basic_json_view/operator_bool/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::operator<<', 'Operator', 'api/basic_json_view/operator_ltlt/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::operator[]', 'Operator', 'api/basic_json_view/operator[]/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::operator==', 'Operator', 'api/basic_json_view/operator_eq/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::operator!=', 'Operator', 'api/basic_json_view/operator_ne/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::size', 'Method', 'api/basic_json_view/size/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::source_offset', 'Method', 'api/basic_json_view/source_offset/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::type', 'Method', 'api/basic_json_view/type/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::type_name', 'Method', 'api/basic_json_view/type_name/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::value', 'Method', 'api/basic_json_view/value/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json', 'Class', 'api/json/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('json_document', 'Class', 'api/json_document/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('json_editable_document', 'Class', 'api/json_editable_document/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('json_editable_view', 'Class', 'api/json_editable_view/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('json_view', 'Class', 'api/json_view/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer', 'Class', 'api/json_pointer/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::back', 'Method', 'api/json_pointer/back/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::empty', 'Method', 'api/json_pointer/empty/index.html');
@@ -162,6 +229,10 @@ INSERT INTO searchIndex(name, type, path) VALUES ('operator""_json_pointer', 'Li
 INSERT INTO searchIndex(name, type, path) VALUES ('operator<<', 'Operator', 'api/operator_ltlt/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('operator>>', 'Operator', 'api/operator_gtgt/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('ordered_json', 'Class', 'api/ordered_json/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('ordered_json_document', 'Class', 'api/ordered_json_document/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('ordered_json_editable_document', 'Class', 'api/ordered_json_editable_document/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('ordered_json_editable_view', 'Class', 'api/ordered_json_editable_view/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('ordered_json_view', 'Class', 'api/ordered_json_view/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('ordered_map', 'Class', 'api/ordered_map/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('std::hash<basic_json>', 'Class', 'api/basic_json/std_hash/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('std::swap<basic_json>', 'Function', 'api/basic_json/std_swap/index.html');
@@ -191,6 +262,7 @@ INSERT INTO searchIndex(name, type, path) VALUES ('Iterators', 'Guide', 'feature
 INSERT INTO searchIndex(name, type, path) VALUES ('JSON Merge Patch', 'Guide', 'features/merge_patch/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('JSON Patch and Diff', 'Guide', 'features/json_patch/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('JSON Pointer', 'Guide', 'features/json_pointer/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('Zero-copy JSON views', 'Guide', 'features/json_view/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('nlohmann Namespace', 'Guide', 'features/namespace/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('Types', 'Guide', 'features/types/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('Types: Number Handling', 'Guide', 'features/types/number_handling/index.html');
@@ -245,3 +317,5 @@ INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_JSON_SERIALIZE_ENUM'
 INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_JSON_VERSION_MAJOR', 'Macro', 'api/macros/nlohmann_json_version_major/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_JSON_VERSION_MINOR', 'Macro', 'api/macros/nlohmann_json_version_major/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_JSON_VERSION_PATCH', 'Macro', 'api/macros/nlohmann_json_version_major/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('JSON_VIEW_NO_SIMD', 'Macro', 'api/macros/json_view_no_simd/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('JSON_VIEW_USE_SSSE3', 'Macro', 'api/macros/json_view_use_ssse3/index.html');
@@ -219,6 +219,7 @@ Strong exception safety: if an exception occurs, the original value stays intact
 - documentation on [checked access](../../features/element_access/checked_access.md)
 - [`operator[]`](operator%5B%5D.md) for unchecked access by reference
 - [`value`](value.md) for access with default value
+- [basic_json_view::at](../basic_json_view/at.md) - the same access on a zero-copy view

 ## Version history

@@ -58,6 +58,7 @@ Constant.
 ## See also

 - [front](front.md) to access the first element
+- [basic_json_view::back](../basic_json_view/back.md) - the same access on a zero-copy view

 ## Version history

@@ -139,8 +139,8 @@ basic_json(basic_json&& other) noexcept;

    - In case of a `#!json null` type, [invalid_iterator.206](../../home/exceptions.md#jsonexceptioninvalid_iterator206)
      is thrown.
-    - In case of other primitive types (number, boolean, or string), `first` must be `begin()` and `last` must be
-      `end()`. In this case, the value is copied. Otherwise,
+    - In case of other primitive types (number, boolean, string, or binary), `first` must be `begin()` and `last`
+      must be `end()`. In this case, the value is copied. Otherwise,
      [`invalid_iterator.204`](../../home/exceptions.md#jsonexceptioninvalid_iterator204) is thrown.
    - In case of structured types (array, object), the constructor behaves as similar versions for `std::vector` or
      `std::map`; that is, a JSON array or object is constructed from the values in the range.
@@ -242,8 +242,8 @@ basic_json(basic_json&& other) noexcept;
      and `last` are not compatible (i.e., do not belong to the same JSON value). In this case, the range
      `[first, last)` is undefined.
    - Throws [`invalid_iterator.204`](../../home/exceptions.md#jsonexceptioninvalid_iterator204) if iterators `first`
-      and `last` belong to a primitive type (number, boolean, or string), but `first` does not point to the first
-      element anymore. In this case, the range `[first, last)` is undefined. See the example code below.
+      and `last` belong to a primitive type (number, boolean, string, or binary), but `first` does not point to the
+      first element anymore. In this case, the range `[first, last)` is undefined. See the example code below.
    - Throws [`invalid_iterator.206`](../../home/exceptions.md#jsonexceptioninvalid_iterator206) if iterators `first`
      and `last` belong to a `#!json null` value. In this case, the range `[first, last)` is undefined.
 8. (none)
@@ -423,6 +423,8 @@ basic_json(basic_json&& other) noexcept;
 4. Since version 3.2.0.
 5. Since version 1.0.0.
 6. Since version 1.0.0.
-7. Since version 1.0.0.
+7. Since version 1.0.0. Fixed in version 3.13.0 to also check the iterator range for binary values; before, a range
+   that did not cover the whole value (such as `(end(), end())`) was accepted and the whole binary value was copied,
+   unlike the other primitive types.
 8. Since version 1.0.0.
 9. Since version 1.0.0.
@@ -37,6 +37,12 @@ Constant.
    --8<-- "examples/begin.output"
    ```

+## See also
+
+- [end](end.md) - returns an iterator to one past the last element
+- [basic_json_view::begin](../basic_json_view/begin.md) - the same iteration on a zero-copy view (in document order,
+  not sorted by key)
+
 ## Version history

 - Added in version 1.0.0.
@@ -36,6 +36,11 @@ Constant.
    --8<-- "examples/cbegin.output"
    ```

+## See also
+
+- [cend](cend.md) - returns a const iterator to one past the last element
+- [basic_json_view::cbegin](../basic_json_view/cbegin.md) - the same iteration on a zero-copy view
+
 ## Version history

 - Added in version 1.0.0.
@@ -36,6 +36,11 @@ Constant.
    --8<-- "examples/cend.output"
    ```

+## See also
+
+- [cbegin](cbegin.md) - returns a const iterator to the first element
+- [basic_json_view::cend](../basic_json_view/cend.md) - the same iteration on a zero-copy view
+
 ## Version history

 - Added in version 1.0.0.
@@ -7,15 +7,15 @@ void clear() noexcept;
 Clears the content of a JSON value and resets it to the default value as if [`basic_json(value_t)`](basic_json.md) would
 have been called with the current value type from [`type()`](type.md):

-| Value type | initial value        |
-|------------|----------------------|
-| null       | `null`               |
-| boolean    | `false`              |
-| string     | `""`                 |
-| number     | `0`                  |
-| binary     | An empty byte vector |
-| object     | `{}`                 |
-| array      | `[]`                 |
+| Value type | initial value                           |
+|------------|-----------------------------------------|
+| null       | `null`                                  |
+| boolean    | `false`                                 |
+| string     | `""`                                    |
+| number     | `0`                                     |
+| binary     | An empty byte vector with no subtype    |
+| object     | `{}`                                    |
+| array      | `[]`                                    |

 Has the same effect as calling

@@ -56,3 +56,4 @@ All iterators, pointers, and references related to this container are invalidate

 - Added in version 1.0.0.
 - Added support for binary types in version 3.8.0.
+- Fixed in version 3.13.0 to also clear the subtype of a binary value; before, the subtype was left unchanged.
@@ -58,6 +58,10 @@ Logarithmic in the size of the JSON object.

 - This method always returns `#!cpp false` when executed on a JSON type that is not an object.
 - This method can be executed on any JSON value type.
+- Calling this function with an integer argument (for example, `#!cpp contains(0)`) does not compile: such an argument
+  would otherwise implicitly convert to a null `#!cpp const char*` and, from there, cause undefined behavior when
+  constructing a `#!cpp std::string` for the object key. To check for an array element instead, use [`at`](at.md),
+  [`operator[]`](operator%5B%5D.md), or compare against [`size`](size.md).

 !!! info "Postconditions"

@@ -111,9 +115,12 @@ Logarithmic in the size of the JSON object.

 - [find](find.md) find a value in an object
 - [count](count.md) returns the number of occurrences of a key
+- [basic_json_view::contains](../basic_json_view/contains.md) - the same check on a zero-copy view

 ## Version history

 1. Added in version 3.11.0.
 2. Added in version 3.6.0. Extended template `KeyType` to support comparable types in version 3.11.0.
 3. Added in version 3.7.0.
+4. Deleted overloads for integral key types added in version 3.13.0 to reject such calls at compile time instead of
+   causing undefined behavior at runtime.
@@ -40,7 +40,11 @@ Logarithmic in the size of the JSON object.

 ## Notes

-This method always returns `0` when executed on a JSON type that is not an object.
+- This method always returns `0` when executed on a JSON type that is not an object.
+- Calling this function with an integer argument (for example, `#!cpp count(0)`) does not compile: such an argument
+  would otherwise implicitly convert to a null `#!cpp const char*` and, from there, cause undefined behavior when
+  constructing a `#!cpp std::string` for the object key. To check for an array element instead, use [`at`](at.md),
+  [`operator[]`](operator%5B%5D.md), or compare against [`size`](size.md).

 ## Examples

@@ -76,8 +80,11 @@ This method always returns `0` when executed on a JSON type that is not an objec

 - [find](find.md) find a value in an object
 - [contains](contains.md) checks whether a key exists
+- [basic_json_view::count](../basic_json_view/count.md) - the same check on a zero-copy view

 ## Version history

 1. Added in version 3.11.0.
 2. Added in version 1.0.0. Changed parameter `key` type to `KeyType&&` in version 3.11.0.
+3. Deleted overload for integral key types added in version 3.13.0 to reject such calls at compile time instead of
+   causing undefined behavior at runtime.
@@ -60,6 +60,9 @@ Linear.

 ## Notes

+Floating-point numbers are written with the fewest digits that read back as the same value (for `#!cpp double`; see
+[number handling](../../features/types/number_handling.md#number-serialization)).
+
 Binary values are serialized as an object containing two keys:

 - "bytes": an array of bytes as integers
@@ -86,6 +89,8 @@ Binary values are serialized as an object containing two keys:

 - [to_string](to_string.md) returns a string representation of a JSON value
 - [operator<<](../operator_ltlt.md) serialize to stream
+- [`basic_json_view::dump`](../basic_json_view/dump.md) the corresponding function of `basic_json_view`, serializing
+  directly from a flat index without building a `basic_json` value
 - [Serialization](../../features/serialization.md) - the serialization article

 ## Version history
@@ -94,3 +99,5 @@ Binary values are serialized as an object containing two keys:
 - Indentation character `indent_char`, option `ensure_ascii` and exceptions added in version 3.0.0.
 - Error handlers added in version 3.4.0.
 - Serialization of binary values added in version 3.8.0.
+- Doubles are written with the shortest digits (Żmij instead of Grisu2) since version 3.13.0; about 0.1% of doubles are
+  written differently, most of them with fewer digits.
@@ -60,6 +60,10 @@ itself is empty which is `#!cpp false` in the case of a string.
    --8<-- "examples/empty.output"
    ```

+## See also
+
+- [basic_json_view::empty](../basic_json_view/empty.md) - the same check on a zero-copy view
+
 ## Version history

 - Added in version 1.0.0.
@@ -37,6 +37,11 @@ Constant.
    --8<-- "examples/end.output"
    ```

+## See also
+
+- [begin](begin.md) - returns an iterator to the first element
+- [basic_json_view::end](../basic_json_view/end.md) - the same iteration on a zero-copy view
+
 ## Version history

 - Added in version 1.0.0.
@@ -44,7 +44,11 @@ Logarithmic in the size of the JSON object.

 ## Notes

-This method always returns `end()` when executed on a JSON type that is not an object.
+- This method always returns `end()` when executed on a JSON type that is not an object.
+- Calling this function with an integer argument (for example, `#!cpp find(0)`) does not compile: such an argument
+  would otherwise implicitly convert to a null `#!cpp const char*` and, from there, cause undefined behavior when
+  constructing a `#!cpp std::string` for the object key. To access an array element instead, use [`at`](at.md),
+  [`operator[]`](operator%5B%5D.md), or compare against [`size`](size.md).

 ## Examples

@@ -80,8 +84,11 @@ This method always returns `end()` when executed on a JSON type that is not an o

 - [count](count.md) returns the number of occurrences of a key
 - [contains](contains.md) checks whether a key exists
+- [basic_json_view::find](../basic_json_view/find.md) - the same lookup on a zero-copy view

 ## Version history

 1. Added in version 3.11.0.
 2. Added in version 1.0.0. Changed to support comparable types in version 3.11.0.
+3. Deleted overloads for integral key types added in version 3.13.0 to reject such calls at compile time instead of
+   causing undefined behavior at runtime.
@@ -51,6 +51,7 @@ Constant.
 ## See also

 - [back](back.md) to access the last element
+- [basic_json_view::front](../basic_json_view/front.md) - the same access on a zero-copy view

 ## Version history

@@ -163,6 +163,8 @@ overload (3).
 - [get_ref](get_ref.md) get a reference to the stored value
 - [operator ValueType](operator_ValueType.md) get a value via implicit conversion
 - [Converting values](../../features/conversions.md) - the type conversions article
+- [basic_json_view::get](../basic_json_view/get.md) - the same conversion on a zero-copy view (many types are
+  converted without ever building a `basic_json` value)

 ## Version history

@@ -61,6 +61,8 @@ Constant.
 ## See also

 - [get_ptr()](get_ptr.md) get a pointer value
+- [basic_json_view::get_string](../basic_json_view/get_string.md) - the closest counterpart on a zero-copy view: a
+  string without a copy, but as a view rather than a reference to a value that must already exist

 ## Version history

@@ -67,6 +67,7 @@ Depends on the `json_serializer<ValueType>::from_json()` implementation.
 - [get_ref](get_ref.md) get a reference to the stored value
 - [get_ptr](get_ptr.md) get a pointer to the stored value
 - [Converting values](../../features/conversions.md) - the type conversions article
+- [basic_json_view::get_to](../basic_json_view/get_to.md) - the same conversion on a zero-copy view

 ## Version history

@@ -195,5 +195,7 @@ Strong exception safety: if an exception occurs, the original value stays intact
 1. Added in version 1.0.0.
 2. Added in version 1.0.0.
 3. Added in version 1.0.0.
-4. Added in version 1.0.0.
+4. Added in version 1.0.0. Fixed in version 3.13.0 to copy the values before inserting; before, an `ilist` that
+   referred to elements of the array being inserted into could insert wrong values, because the range insert could
+   move from or shift an element before it was copied.
 5. Added in version 3.0.0.
@@ -34,6 +34,10 @@ Constant.
    --8<-- "examples/is_array.output"
    ```

+## See also
+
+- [basic_json_view::is_array](../basic_json_view/is_array.md) - the same check on a zero-copy view
+
 ## Version history

 - Added in version 1.0.0.
@@ -34,6 +34,10 @@ Constant.
    --8<-- "examples/is_binary.output"
    ```

+## See also
+
+- [basic_json_view::is_binary](../basic_json_view/is_binary.md) - the same check on a zero-copy view
+
 ## Version history

 - Added in version 3.8.0.
@@ -34,6 +34,10 @@ Constant.
    --8<-- "examples/is_boolean.output"
    ```

+## See also
+
+- [basic_json_view::is_boolean](../basic_json_view/is_boolean.md) - the same check on a zero-copy view
+
 ## Version history

 - Added in version 1.0.0.
@@ -69,6 +69,11 @@ with `allow_exceptions` set to `#!cpp false`: a parse error then yields a discar
    --8<-- "examples/is_discarded.output"
    ```

+## See also
+
+- [basic_json_view::is_discarded](../basic_json_view/is_discarded.md) - the corresponding check on a zero-copy view,
+  which is `#!cpp true` if the view refers to no value
+
 ## Version history

 - Added in version 1.0.0.
@@ -34,6 +34,10 @@ Constant.
    --8<-- "examples/is_null.output"
    ```

+## See also
+
+- [basic_json_view::is_null](../basic_json_view/is_null.md) - the same check on a zero-copy view
+
 ## Version history

 - Added in version 1.0.0.
@@ -49,6 +49,7 @@ constexpr bool is_number() const noexcept
 - [is_number_integer()](is_number_integer.md) check if the value is an integer or unsigned integer number
 - [is_number_unsigned()](is_number_unsigned.md) check if the value is an unsigned integer number
 - [is_number_float()](is_number_float.md) check if the value is a floating-point number
+- [basic_json_view::is_number](../basic_json_view/is_number.md) - the same check on a zero-copy view

 ## Version history

@@ -40,6 +40,7 @@ Constant.
 - [is_number()](is_number.md) check if the value is a number
 - [is_number_integer()](is_number_integer.md) check if the value is an integer or unsigned integer number
 - [is_number_unsigned()](is_number_unsigned.md) check if the value is an unsigned integer number
+- [basic_json_view::is_number_float](../basic_json_view/is_number_float.md) - the same check on a zero-copy view

 ## Version history

@@ -40,6 +40,7 @@ Constant.
 - [is_number()](is_number.md) check if the value is a number
 - [is_number_unsigned()](is_number_unsigned.md) check if the value is an unsigned integer number
 - [is_number_float()](is_number_float.md) check if the value is a floating-point number
+- [basic_json_view::is_number_integer](../basic_json_view/is_number_integer.md) - the same check on a zero-copy view

 ## Version history

@@ -40,6 +40,7 @@ Constant.
 - [is_number()](is_number.md) check if the value is a number
 - [is_number_integer()](is_number_integer.md) check if the value is an integer or unsigned integer number
 - [is_number_float()](is_number_float.md) check if the value is a floating-point number
+- [basic_json_view::is_number_unsigned](../basic_json_view/is_number_unsigned.md) - the same check on a zero-copy view

 ## Version history

@@ -34,6 +34,10 @@ Constant.
    --8<-- "examples/is_object.output"
    ```

+## See also
+
+- [basic_json_view::is_object](../basic_json_view/is_object.md) - the same check on a zero-copy view
+
 ## Version history

 - Added in version 1.0.0.
@@ -62,6 +62,7 @@ This library extends primitive types to binary types, because binary types are r
 - [is_boolean()](is_boolean.md) returns whether the JSON value is a boolean
 - [is_number()](is_number.md) returns whether the JSON value is a number
 - [is_binary()](is_binary.md) returns whether the JSON value is a binary array
+- [basic_json_view::is_primitive](../basic_json_view/is_primitive.md) - the same check on a zero-copy view

 ## Version history

@@ -34,6 +34,10 @@ Constant.
    --8<-- "examples/is_string.output"
    ```

+## See also
+
+- [basic_json_view::is_string](../basic_json_view/is_string.md) - the same check on a zero-copy view
+
 ## Version history

 - Added in version 1.0.0.
@@ -57,6 +57,7 @@ Note that though strings are containers in C++, they are treated as primitive va
 - [is_primitive()](is_primitive.md) returns whether JSON value is primitive
 - [is_array()](is_array.md) returns whether the value is an array
 - [is_object()](is_object.md) returns whether the value is an object
+- [basic_json_view::is_structured](../basic_json_view/is_structured.md) - the same check on a zero-copy view

 ## Version history

@@ -99,6 +99,8 @@ When iterating over an array, `key()` will return the index of the element as st

 - [begin](begin.md) returns an iterator to the first element
 - [end](end.md) returns an iterator to one past the last element
+- [basic_json_view::items](../basic_json_view/items.md) - the same range on a zero-copy view (`#!cpp const auto`,
+  not `#!cpp const auto&`: items are produced on the fly)

 ## Version history

@@ -23,9 +23,10 @@ type to use.
 ## Template parameters

 `NumberFloatType`
-:   the type to store floating-point numbers. Parsing and serialization are implemented in terms of
-    `#!cpp std::strtof`/`#!cpp std::strtod`/`#!cpp std::strtold` and `#!cpp std::snprintf`, so the type must be
-    `#!cpp float`, `#!cpp double`, or `#!cpp long double`. The
+:   the type to store floating-point numbers. The parser converts `#!cpp float`, `#!cpp double`, and a
+    `#!cpp long double` that is IEEE 754 binary64 itself and other `#!cpp long double` formats with
+    `#!cpp std::from_chars` or `#!cpp std::strtold`, and serialization falls back to `#!cpp std::snprintf`, so the
+    type must be `#!cpp float`, `#!cpp double`, or `#!cpp long double`. The
    [binary formats](../../features/binary_formats/index.md) additionally require `#!cpp float` or `#!cpp double`,
    because they have no encoding for `#!cpp long double`. See
    [Template Parameter Requirements](../../features/types/template_parameters.md#numberfloattype).
@@ -70,6 +70,9 @@ Strong exception safety: if an exception occurs, the original value stays intact
 1. The function can throw the following exceptions:
    - Throws [`type_error.305`](../../home/exceptions.md#jsonexceptiontype_error305) if the JSON value is not an array
      or null; in that case, using the `[]` operator with an index makes no sense.
+    - Throws `#!cpp std::length_error` if `idx` equals the maximum value of `size_type`; the array is left unchanged.
+      (This is the one index for which growing the array to hold it cannot be expressed as a `size_type` size, the same
+      way an oversized [`resize`](https://en.cppreference.com/w/cpp/container/vector/resize) throws.)
 2. The function can throw the following exceptions:
    - Throws [`type_error.305`](../../home/exceptions.md#jsonexceptiontype_error305) if the JSON value is not an object
      or null; in that case, using the `[]` operator with a key makes no sense.
@@ -254,10 +257,13 @@ Strong exception safety: if an exception occurs, the original value stays intact
 - documentation on [runtime assertions](../../features/assertions.md)
 - see [`at`](at.md) for access by reference with range checking
 - see [`value`](value.md) for access with default value
+- [basic_json_view::operator[]](../basic_json_view/operator%5B%5D.md) - the same access on a zero-copy view (always
+  returns a discarded view instead of assuming undefined behavior)

 ## Version history

-1. Added in version 1.0.0.
+1. Added in version 1.0.0. Fixed in version 3.13.0 to throw `#!cpp std::length_error` instead of emptying the array and
+   accessing it out of bounds when `idx` equals the maximum value of `size_type`.
 2. Added in version 1.0.0. Added overloads for `T* key` in version 1.1.0. Removed overloads for `T* key` (replaced by 3)
   in version 3.11.0.
 3. Added in version 3.11.0. Fixed in version 3.13.0 to consistently accept `std::string_view`-convertible keys, as
@@ -166,6 +166,8 @@ Linear.

 - [operator!=](operator_ne.md) compare for inequality
 - [operator<=>](operator_spaceship.md) comparison: 3-way (C++20)
+- [basic_json_view::operator==](../basic_json_view/operator_eq.md) - the same comparison on a zero-copy view, without
+  building a `basic_json` value for it

 ## Version history

@@ -89,6 +89,12 @@ Linear.
    --8<-- "examples/operator__notequal__nullptr_t.output"
    ```

+## See also
+
+- [operator==](operator_eq.md) compare for equality
+- [basic_json_view::operator!=](../basic_json_view/operator_ne.md) - the same comparison on a zero-copy view, without
+  building a `basic_json` value for it
+
 ## Version history

 1. Added in version 1.0.0. Added C++20 member functions in version 3.11.0. Changed in version 3.13.0 to remove 
@@ -88,7 +88,12 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
 ## Exceptions

 - Throws [`parse_error.101`](../../home/exceptions.md#jsonexceptionparse_error101) in case of an unexpected token, or
-  empty input like a null `FILE*` or `char*` pointer.
+  empty input like a null `FILE*` or `char*` pointer, or an `std::istream` without a stream buffer
+  (`#!cpp i.rdbuf() == nullptr`, for instance `#!cpp std::istream(nullptr)`).
+- If reading from an `std::istream` reaches the end of the input and `eofbit` is part of the stream's
+  [`exceptions()`](https://en.cppreference.com/w/cpp/io/basic_ios/exceptions) mask, the `std::ios_base::failure`
+  thrown by the stream itself propagates instead of a `parse_error`, the same as it would for the standard library's
+  own extraction operators.

 ## Complexity

@@ -254,6 +259,8 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
 - Extended overload (2) to accept heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
 - `JSON_STRICT_NUL_HANDLING` added in version 3.13.0 to optionally reject a NUL byte in the input instead of treating
  it as end of input; planned to become the default in version 4.0.0.
+- Extended empty-input detection to also cover an `std::istream` without a stream buffer, and fixed a crash
+  (`std::terminate`) when parsing from an `std::istream` with `eofbit` in its exception mask, in version 3.13.0.

 !!! warning "Deprecation"

@@ -100,3 +100,6 @@ the latter case, it is skipped completely, or replaced by `null` if it is the to
 - Added in version 1.0.0.
 - Fixed in version 3.13.0 to also remove discarded values from a parent object; before, discarding an array or a value
  stored under an object key left a discarded member behind, which made the parse result serialize to invalid JSON.
+- Fixed in version 3.13.0 so that discarding an array or object at its start event also hides its content from the
+  callback, as documented above; before, the callback was still called for the content, and the key of every member of
+  a discarded object was kept in memory until the parse ended.
@@ -51,6 +51,10 @@ JSON value which is `1` in the case of a string.
    --8<-- "examples/size.output"
    ```

+## See also
+
+- [basic_json_view::size](../basic_json_view/size.md) - the same function on a zero-copy view
+
 ## Version history

 - Added in version 1.0.0.
@@ -6,7 +6,9 @@ void swap(reference other) noexcept (
    std::is_nothrow_move_constructible<value_t>::value &&
    std::is_nothrow_move_assignable<value_t>::value &&
    std::is_nothrow_move_constructible<json_value>::value &&
-    std::is_nothrow_move_assignable<json_value>::value
+    std::is_nothrow_move_assignable<json_value>::value &&
+    std::is_nothrow_move_constructible<json_base_class_t>::value &&
+    std::is_nothrow_move_assignable<json_base_class_t>::value
 );

 // (2)
@@ -14,7 +16,9 @@ friend void swap(reference left, reference right) noexcept (
    std::is_nothrow_move_constructible<value_t>::value &&
    std::is_nothrow_move_assignable<value_t>::value &&
    std::is_nothrow_move_constructible<json_value>::value &&
-    std::is_nothrow_move_assignable<json_value>::value
+    std::is_nothrow_move_assignable<json_value>::value &&
+    std::is_nothrow_move_constructible<json_base_class_t>::value &&
+    std::is_nothrow_move_assignable<json_base_class_t>::value
 );

 // (3)
@@ -37,11 +41,15 @@ void swap(typename binary_t::container_type& other);
   individual elements. All iterators and references remain valid. The past-the-end iterator is invalidated. If macro
   [`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) is defined to `#!cpp 1`, the
   [`start_pos()`](start_pos.md)/[`end_pos()`](end_pos.md) diagnostic positions are exchanged along with the value.
+   The [`json_base_class_t`](json_base_class_t.md) subobject is exchanged along with the value as well, the same way it
+   is copied or moved by the copy/move constructors and assignment operators.
 2. Exchanges the contents of the JSON value from `left` with those of `right`. Does not invoke any move, copy, or swap
   operations on individual elements. All iterators and references remain valid. The past-the-end iterator is
   invalidated. Implemented as a friend function callable via ADL. If macro
   [`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) is defined to `#!cpp 1`, the
   [`start_pos()`](start_pos.md)/[`end_pos()`](end_pos.md) diagnostic positions are exchanged along with the value.
+   The [`json_base_class_t`](json_base_class_t.md) subobject is exchanged along with the value as well, the same way it
+   is copied or moved by the copy/move constructors and assignment operators.
 3. Exchanges the contents of a JSON array with those of `other`. Does not invoke any move, copy, or swap operations on
   individual elements. All iterators and references remain valid. The past-the-end iterator is invalidated. 
 4. Exchanges the contents of a JSON object with those of `other`. Does not invoke any move, copy, or swap operations on
@@ -164,8 +172,8 @@ Constant.

 ## Version history

-1. Since version 1.0.0.
-2. Since version 1.0.0.
+1. Since version 1.0.0. Exchanges the `json_base_class_t` subobject along with the value since version 3.13.0.
+2. Since version 1.0.0. Exchanges the `json_base_class_t` subobject along with the value since version 3.13.0.
 3. Since version 1.0.0.
 4. Since version 1.0.0.
 5. Since version 1.0.0.
@@ -43,6 +43,9 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
 - Throws [`out_of_range.412`](../../home/exceptions.md#jsonexceptionout_of_range412) if the length of a document, array,
  string, or binary value exceeds the range of the 32-bit BSON length field; example:
  `"BSON length 2147483661 exceeds maximum of 2147483647"`
+- Throws [`out_of_range.415`](../../home/exceptions.md#jsonexceptionout_of_range415) if the subtype of a binary value
+  exceeds 255, the maximum of the BSON binary subtype; example:
+  `"subtype 70000 is too large for the BSON binary subtype (max 255)"`

 ## Complexity

@@ -78,3 +81,4 @@ pass before anything is written.

 - Added in version 3.4.0.
 - Linear in the size of `j`, and no longer limited by the call stack for deeply nested values, since version 3.13.0.
+- `out_of_range.415` is now detected before anything is written, like the other exceptions above, since version 3.13.0.
@@ -76,3 +76,6 @@ Linear in the size of the JSON value `j`.

 - Added in version 2.0.9.
 - Throws `out_of_range.412` and `out_of_range.415` since version 3.13.0.
+- Fixed in version 3.13.0 to serialize `number_integer_t`/`number_unsigned_t` pairs of different width correctly;
+  before, integers could be serialized with the wrong value if `number_integer_t` was narrower than
+  `number_unsigned_t`.
@@ -47,6 +47,10 @@ Constant.
    --8<-- "examples/type.output"
    ```

+## See also
+
+- [basic_json_view::type](../basic_json_view/type.md) - the same function on a zero-copy view
+
 ## Version history

 - Added in version 1.0.0.
@@ -52,6 +52,11 @@ Constant.
    --8<-- "examples/type_name.output"
    ```

+## See also
+
+- [type](type.md) - return the type of the JSON value
+- [basic_json_view::type_name](../basic_json_view/type_name.md) - the same function on a zero-copy view
+
 ## Version history

 - Added in version 1.0.0.
@@ -52,6 +52,14 @@ This is equivalent to Python's `dict.get(key, default)`.
    - Unlike [`operator[]`](operator[].md), this function does not implicitly add an element to the position defined by
     `key`/`ptr` key. This function is furthermore also applicable to const objects.

+!!! note "Integer keys"
+
+    Calling this function with an integer `key` argument (for example, `#!cpp value(0, 1)`) does not compile in
+    C++11, where `object_comparator_t` is not transparent: such an argument would otherwise implicitly convert to a
+    null `#!cpp const char*` and, from there, cause undefined behavior when constructing a `#!cpp std::string` for the
+    object key. To access an array element with a default value, use [`at`](at.md) together with a `#!cpp try`/`#!cpp
+    catch` block, or compare against [`size`](size.md) instead.
+
 ## Template parameters

 `KeyType`
@@ -181,10 +189,13 @@ changes to any JSON value.

 - see [`at`](at.md) for access by reference with range checking
 - see [`operator[]`](operator%5B%5D.md) for unchecked access by reference
+- [basic_json_view::value](../basic_json_view/value.md) - the same access on a zero-copy view

 ## Version history

-1. Added in version 1.0.0. Changed parameter `default_value` type from `const ValueType&` to `ValueType&&` in version 3.11.0.
+1. Added in version 1.0.0. Changed parameter `default_value` type from `const ValueType&` to `ValueType&&` in version
+   3.11.0. Deleted overload for integral key types added in version 3.13.0 to reject such calls at compile time
+   instead of causing undefined behavior at runtime.
 2. Added in version 3.11.0. Made `ValueType` the first template parameter in version 3.11.2.
 3. Added in version 2.0.2. Extended to work with arrays in version 3.13.0, including fixing an issue where resolving
   `ptr` through an array unexpectedly threw `out_of_range` instead of returning the resolved element (or
@@ -0,0 +1,67 @@
+# <small>nlohmann::basic_json_document::</small>accept
+
+```cpp
+template<typename InputType>
+static bool accept(InputType&& input,
+                   const bool ignore_comments = false,
+                   const bool ignore_trailing_commas = false);
+```
+
+Checks whether the input is valid JSON, accepting and rejecting exactly what
+[`BasicJsonType::accept()`](../basic_json/accept.md) does, with the same options. Unlike [`parse()`](parse.md), this
+function never throws an exception for invalid input, and the returned `#!cpp bool` is the only result -- no document
+is returned.
+
+## Template parameters
+
+`InputType`
+:   A compatible input; see [`parse`](parse.md#template-parameters).
+
+## Parameters
+
+`input` (in)
+:   Input to check.
+
+`ignore_comments` (in)
+:   whether comments should be ignored and treated like whitespace (`#!cpp true`) or yield a parse error
+    (`#!cpp false`); (optional, `#!cpp false` by default)
+
+`ignore_trailing_commas` (in)
+:   whether trailing commas in arrays or objects should be ignored and treated like whitespace (`#!cpp true`) or
+    yield a parse error (`#!cpp false`); (optional, `#!cpp false` by default)
+
+## Return value
+
+Whether the input is valid JSON.
+
+## Exception safety
+
+Strong guarantee: this function itself never throws for an invalid input; it can only throw what allocating the
+input's own copy (for inputs that are always read into a buffer) throws.
+
+## Complexity
+
+Linear in the length of the input.
+
+## Examples
+
+??? example
+
+    ```cpp
+    --8<-- "examples/basic_json_document__accept.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_document__accept.output"
+    ```
+
+## See also
+
+- [parse](parse.md) - deserialize from a compatible input
+- [`BasicJsonType::accept`](../basic_json/accept.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,58 @@
+# <small>nlohmann::basic_json_document::</small>basic_json_document
+
+```cpp
+// (1)
+basic_json_document() = default;
+
+// (2)
+basic_json_document(basic_json_document&& other) noexcept = default;
+
+// (3)
+basic_json_document(const basic_json_document&) = delete;
+```
+
+1. Creates an empty (discarded) document: [`root()`](root.md) returns a discarded view, and
+   [`is_discarded()`](is_discarded.md) is `#!cpp true`.
+2. Move constructor. Takes over `other`'s index and, if owned, its text; `other` is left as an empty document. Views
+   taken from `other` before the move remain valid, because the index is heap-allocated independently of the
+   `basic_json_document` object.
+3. `basic_json_document` is move-only. Copying is disabled because it would either duplicate a potentially large index
+   and text, or leave two documents claiming to borrow the same buffer.
+
+## Parameters
+
+`other` (in)
+:   another document to move the index and text from
+
+## Exception safety
+
+No-throw guarantee: the default and move constructors never throw exceptions.
+
+## Complexity
+
+Constant, for the default and move constructors.
+
+## Examples
+
+??? example
+
+    The example below shows the default constructor and demonstrates that `basic_json_document` is move-only.
+
+    ```cpp
+    --8<-- "examples/basic_json_document__basic_json_document.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_document__basic_json_document.output"
+    ```
+
+## See also
+
+- [parse](parse.md) - deserialize from a compatible input
+- [is_discarded](is_discarded.md) - return whether the last parse failed
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,128 @@
+# <small>nlohmann::basic_json_document::</small>erase
+
+```cpp
+// (1)
+std::size_t erase(view_type object, string_view_t key);
+
+// (2)
+template<typename I>
+void erase(view_type array, I idx);
+
+// (3)
+std::size_t erase(const json_pointer& ptr);
+```
+
+Only an **editable** document (`#!cpp Editable == true`, e.g. [`json_editable_document`](../json_editable_document.md))
+has `erase`; calling it on a read-only `basic_json_document` fails to compile (`#!cpp static_assert`).
+
+1. Removes every member of `object` whose key is `key` (see [Notes](#notes) on duplicate keys) and returns how many
+   were removed; `#!cpp 0` if `object` has no member with this key.
+2. Removes the element at index `idx` of `array`, which must already exist (`#!cpp idx < array.size()`).
+3. Removes the value the JSON pointer `ptr` refers to, relative to [`root()`](root.md), and returns how many values
+   were removed: the *parent* of the target must already exist, and the target itself is removed as in 1. (an object
+   member; `#!cpp 0` or more) or 2. (an array element; always `#!cpp 1`). `ptr` must not be empty -- [`root()`](root.md)
+   itself cannot be erased.
+
+## Template parameters
+
+`I`
+:   an integral type other than `#!cpp bool`, deduced (overloads taking a `#!cpp bool` or a non-integral type for
+    `idx` do not participate in overload resolution).
+
+## Parameters
+
+`object` (in)
+:   the object to remove a member of
+
+`array` (in)
+:   the array to remove an element of
+
+`key` (in)
+:   the key of the member(s) to remove
+
+`idx` (in)
+:   the index of the element to remove; a negative value throws (see [Exceptions](#exceptions))
+
+`ptr` (in)
+:   a JSON pointer to the value to remove, relative to `root()`
+
+## Return value
+
+1. the number of removed members (`#!cpp 0` if `object` had none with this `key`)
+2. (nothing)
+3. the number of removed values (`#!cpp 0` or more for an object member, always `#!cpp 1` for an array element)
+
+## Exceptions
+
+1. Throws [`type_error.307`](../../home/exceptions.md#jsonexceptiontype_error307) if `object` is not an object -- the
+   same message [`BasicJsonType::erase`](../basic_json/erase.md) throws for the same type.
+2. Throws `type_error.307` if `array` is not an array. Throws
+   [`out_of_range.401`](../../home/exceptions.md#jsonexceptionout_of_range401) if `idx` is negative, or if
+   `#!cpp idx >= array.size()`.
+3. Throws [`out_of_range.405`](../../home/exceptions.md#jsonexceptionout_of_range405) ("JSON pointer has no parent")
+   if `ptr` is empty. Throws what [`at`](../basic_json_view/at.md) throws (overload 3) for resolving `ptr`'s parent.
+   For the last reference token itself: if the parent is an array, throws what 2. throws for an index that is out of
+   range, or, for a token that is not a valid array index,
+   [`parse_error.106`](../../home/exceptions.md#jsonexceptionparse_error106) (a leading `#!cpp '0'`),
+   [`parse_error.109`](../../home/exceptions.md#jsonexceptionparse_error109) (not a number),
+   [`out_of_range.410`](../../home/exceptions.md#jsonexceptionout_of_range410) (too large for `size_type`), or
+   [`out_of_range.404`](../../home/exceptions.md#jsonexceptionout_of_range404) (an empty token); otherwise (an
+   object, or a primitive value the pointer's parent resolves to) throws what 1. throws.
+
+Every overload also throws [`invalid_iterator.202`](../../home/exceptions.md#jsonexceptioninvalid_iterator202) ("view
+does not belong to this document") if `object`/`array` is a [discarded](../basic_json_view/is_discarded.md) view or a
+view of a *different* document (overloads 1-2 only; overload 3 always starts from this document's own
+[`root()`](root.md)).
+
+## Complexity
+
+1. Linear in the number of members of `object`.
+2. Linear in the number of elements of `array` at or after `idx` (they move one slot over).
+3. Linear in the number of reference tokens of `ptr` and, for each token, in the number of members of the object at
+   that level or the index into the array (as [`at`](../basic_json_view/at.md)), plus the complexity of 1. or 2. for
+   the last token.
+
+## Notes
+
+!!! info "Duplicate keys"
+
+    Overload 1. removes *every* member with `key`, not just the first -- unlike [`set`](set.md), which assigns the
+    first occurrence and drops the rest. This is why it returns a count rather than a single view: there may be
+    more than one member removed, or none.
+
+Like [`set`](set.md) and [`push_back`](push_back.md), `erase` never moves an element's *value*: a view still
+referring to a removed member or element keeps showing what it last held (see [Edits](index.md#edits)) -- it just no
+longer appears when `array`/`object` is read, dumped, or iterated. Removing an element of `array` (2.) does shift the
+*links* to the elements after it, the same way `insert`, `set`, or `push_back` on the same array would; any iterator
+already taken over `array`/`object` is invalidated by an erase, since it was walking the old layout.
+
+## Examples
+
+??? example
+
+    The example below drops a deprecated field and a decommissioned entry from a configuration document -- using all
+    three overloads -- and shows what stays intact that would not with a plain `json`/`ordered_json` value: the order
+    of the fields around the ones removed, and the exact spelling of a number that was never touched.
+
+    ```cpp
+    --8<-- "examples/basic_json_document__erase.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_document__erase.output"
+    ```
+
+## See also
+
+- [insert](insert.md) - insert an element into an array
+- [set](set.md) - replace a value, or set an object member, an array element, or the value a JSON pointer refers to
+- [push_back](push_back.md) - append to an array
+- [root](root.md) - the view of the root value, the starting point of overload 3
+- [`BasicJsonType::erase`](../basic_json/erase.md) - the corresponding function of `basic_json`
+- [Edits](index.md#edits) - what an edit guarantees, for every overload
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,118 @@
+# <small>nlohmann::</small>basic_json_document
+
+<small>Defined in header `<nlohmann/json_view.hpp>`</small>
+
+```cpp
+template<typename BasicJsonType, bool Editable = false>
+class basic_json_document;
+```
+
+A parsed JSON text, held as a flat index of its values
+([16 bytes per value](../../home/architecture.md#node-index-of-json-views)) instead of a tree of `BasicJsonType` values.
+Strings and numbers stay in the source text; only strings that contain escapes are decoded, into one buffer owned by
+the document. [`basic_json_view`](../basic_json_view/index.md) is a read-only handle to one value of a
+`basic_json_document`; [`materialize()`](../basic_json_view/materialize.md) turns a subtree back into the
+`BasicJsonType` value that [`BasicJsonType::parse()`](../basic_json/parse.md) would have produced for it.
+
+A document may **borrow** the text it was parsed from (the caller's buffer must then outlive the document) or **own**
+it (a copy, or an rvalue `#!cpp std::string` that was moved in); see [`owns_source`](owns_source.md). `basic_json_document`
+is move-only: copying a document would either duplicate a potentially large index and text, or leave two documents
+claiming to borrow the same buffer, so it is disabled.
+
+With `#!cpp Editable == true`, the document also offers [`set`](set.md), [`push_back`](push_back.md),
+[`insert`](insert.md), and [`erase`](erase.md) to change values in place, see [Edits](#edits) below. The source text
+itself is never written; a read-only document (`#!cpp Editable == false`, the default) does not carry any of the
+bookkeeping edits need, and calling any of them on one fails to compile (`#!cpp static_assert`).
+
+## Template parameters
+
+`BasicJsonType`
+:   a specialization of [`basic_json`](../basic_json/index.md), for instance [`json`](../json.md) or
+    [`ordered_json`](../ordered_json.md). Only 64-bit `number_integer_t`/`number_unsigned_t` types are supported; this
+    is checked with a `static_assert`.
+
+`Editable`
+:   whether the document supports [`set`](set.md), [`push_back`](push_back.md), [`insert`](insert.md), and
+    [`erase`](erase.md) (optional, `#!cpp false` by default). See [Edits](#edits) below.
+
+## Specializations
+
+- [**json_document**](../json_document.md) - read-only documents of the default specialization [`json`](../json.md)
+- [**ordered_json_document**](../ordered_json_document.md) - read-only documents of
+  [`ordered_json`](../ordered_json.md)
+- [**json_editable_document**](../json_editable_document.md) - editable documents of [`json`](../json.md)
+- [**ordered_json_editable_document**](../ordered_json_editable_document.md) - editable documents of
+  [`ordered_json`](../ordered_json.md)
+
+## Member types
+
+- **view_type** - the type of view returned by [`root()`](root.md) (`#!cpp basic_json_view<BasicJsonType, Editable>`)
+- **value_t** - the JSON type enumeration, see [`basic_json::value_t`](../basic_json/value_t.md)
+
+## Member functions
+
+- [(constructor)](basic_json_document.md)
+
+### Parsing
+
+- [**parse**](parse.md) (_static_) - deserialize from a compatible input, borrowing or owning it as appropriate
+- [**parse_copy**](parse_copy.md) (_static_) - deserialize a copy of a compatible input
+- [**accept**](accept.md) (_static_) - check whether the input is valid JSON
+- [**read**](read.md) - (re-)parse into this document, reusing its memory
+
+### Access
+
+- [**root**](root.md) - the view of the root value
+- [**is_discarded**](is_discarded.md) - return whether the last parse failed
+- [**source**](source.md) - the parsed text
+- [**owns_source**](owns_source.md) - return whether the document holds its own copy of the text
+- [**node_count**](node_count.md) - the number of index entries (values plus object keys)
+- [**memory_usage**](memory_usage.md) - the number of bytes held by the document
+- [**shrink_to_fit**](shrink_to_fit.md) - release unused index capacity
+
+### Images
+
+- [**save**](save.md) - the document as an image that `load()` reads without parsing
+- [**load**](load.md) (_static_) - read an image written by `save()`
+
+### Edits
+
+- [**set**](set.md) - replace a value, or set an object member, an array element, or the value a JSON pointer refers
+  to (`#!cpp Editable` documents only)
+- [**push_back**](push_back.md) - append to an array (`#!cpp Editable` documents only)
+- [**insert**](insert.md) - insert an element into an array before a given position (`#!cpp Editable` documents only)
+- [**erase**](erase.md) - remove an object member, an array element, or the value a JSON pointer refers to
+  (`#!cpp Editable` documents only)
+
+## Edits
+
+An editable document (`#!cpp Editable == true`) can be changed after parsing, with [`set`](set.md),
+[`push_back`](push_back.md), [`insert`](insert.md), and [`erase`](erase.md);
+[`json_editable_document`](../json_editable_document.md) and
+[`ordered_json_editable_document`](../ordered_json_editable_document.md) are the corresponding specializations. A few
+points apply to every edit:
+
+- **The source text is never written**, and the parsed index never moves: every value keeps the node it was parsed
+  into, so [views](../basic_json_view/index.md) taken before an edit stay valid, including
+  [`root()`](root.md). New values (and the element sequences of an edited array/object) go to storage owned by the
+  document, allocated on demand.
+- **A view keeps referring to the same value.** After [`set`](set.md) replaces the value a view refers to, that view
+  sees the new value; a view of a value that a later edit replaces or drops keeps showing what it last held. An edit
+  of an array or object, however, **invalidates the iterators taken over it** (its members may now live in a
+  different sequence), and a string obtained with [`get_string()`](../basic_json_view/get_string.md) stays valid even
+  as further edits happen (earlier buffers of edited text are kept alive, not overwritten).
+- **Values are accepted three ways:** a [`basic_json_view`](../basic_json_view/index.md) of *any* document
+  (read-only or editable; it is copied, nothing is shared with the source document), a `BasicJsonType` value, or
+  anything `BasicJsonType` can be constructed from (numbers, strings, `#!cpp bool`, `#!cpp nullptr`, containers, ...).
+- [`dump()`](../basic_json_view/dump.md) writes an edited document with members in document order, new members at
+  the end, and, with [`number_format::source`](../basic_json_view/number_format.md), keeps the spelling of every
+  number that was not itself edited -- see [Editing a document](../../features/json_view.md#editing-a-document) for
+  why this matters.
+- [`read()`](read.md) discards all edits, [`shrink_to_fit()`](shrink_to_fit.md) does not move the node index once
+  there are edits, and [`memory_usage()`](memory_usage.md) includes the memory edits use.
+  [`source_offset()`](../basic_json_view/source_offset.md) of a value introduced by an edit is
+  `#!cpp static_cast<std::size_t>(-1)`, the same value it reports for a decoded string.
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,114 @@
+# <small>nlohmann::basic_json_document::</small>insert
+
+```cpp
+template<typename I, typename V>
+view_type insert(view_type array, I idx, V&& value);
+```
+
+Only an **editable** document (`#!cpp Editable == true`, e.g. [`json_editable_document`](../json_editable_document.md))
+has `insert`; calling it on a read-only `basic_json_document` fails to compile (`#!cpp static_assert`).
+
+Inserts `value` into `array` as a new element before position `idx`, which must not be past the end
+(`#!cpp idx <= array.size()`; `#!cpp idx == array.size()` appends, like [`push_back`](push_back.md)). Unlike
+[`push_back`](push_back.md), a [null](../basic_json_view/is_null.md) `array` does *not* first become an empty array:
+`array` must already be an array.
+
+`value` is accepted three ways: a [`basic_json_view`](../basic_json_view/index.md) of *any* document -- read-only or
+editable, and it does not have to be `array`'s own document -- which is copied so that nothing is shared with the
+source document afterward; a `BasicJsonType` value; or anything `BasicJsonType` can be constructed from (numbers,
+strings, `#!cpp bool`, `#!cpp nullptr`, containers, ...).
+
+## Template parameters
+
+`I`
+:   an integral type other than `#!cpp bool`, deduced (overloads taking a `#!cpp bool` or a non-integral type for
+    `idx` do not participate in overload resolution).
+
+`V`
+:   the type of `value`, deduced; see above for what is accepted.
+
+## Parameters
+
+`array` (in)
+:   the array to insert into
+
+`idx` (in)
+:   the position to insert `value` before; a negative value throws (see [Exceptions](#exceptions))
+
+`value` (in)
+:   the value to insert
+
+## Return value
+
+a view of the new element, now holding `value`
+
+## Exception safety
+
+Basic exception safety: `value` is fully encoded -- including the checks below -- into storage owned by the document
+before anything already reachable from [`root()`](root.md) is touched, so a failure while encoding `value` (an
+invalid argument, or `#!cpp std::bad_alloc`) leaves the document completely unchanged, other than memory allocated
+for the encoding that is not reclaimed. A failure of a later allocation -- while `array` switches from its parsed
+layout to a growable block, or while that block grows, see [Notes](#notes) -- can still leave `array` already
+switched to that layout even though `value` itself was not inserted.
+
+## Exceptions
+
+Throws [`type_error.309`](../../home/exceptions.md#jsonexceptiontype_error309) if `array` is not an array -- the same
+message [`BasicJsonType::insert`](../basic_json/insert.md) throws for the same type; a null `array` throws this too
+(see above). Throws [`out_of_range.401`](../../home/exceptions.md#jsonexceptionout_of_range401) if `idx` is negative,
+or if `#!cpp idx > array.size()`. Throws
+[`invalid_iterator.202`](../../home/exceptions.md#jsonexceptioninvalid_iterator202) ("view does not belong to this
+document") if `array` is a [discarded](../basic_json_view/is_discarded.md) view or a view of a *different* document.
+Throws [`type_error.302`](../../home/exceptions.md#jsonexceptiontype_error302) if `value` is a
+[discarded](../basic_json_view/is_discarded.md) view or a [discarded](../basic_json/is_discarded.md) `BasicJsonType`
+value, and [`type_error.319`](../../home/exceptions.md#jsonexceptiontype_error319) if `value` is (or contains) a
+binary value -- `BasicJsonType` can hold one, but a `json_document` cannot. Throws
+[`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316) if `value` is (or contains) a string that is
+not valid UTF-8, with the same message [`BasicJsonType::dump()`](../basic_json/dump.md) gives for that string.
+
+## Complexity
+
+Linear in the number of elements of `array` at or after `idx` (they move one slot over), plus time linear in the
+size of `value` to encode it into the document's storage (constant for a scalar, linear in the number of nested
+values for an array or object): like [`push_back`](push_back.md), the elements of `array` move to a growable block
+of links the first time it is inserted into (or [`set`](set.md)/[`push_back`](push_back.md) on), and that block
+grows in amortized constant time; inserting before the end within that block still shifts every later element.
+
+## Notes
+
+Like [`set`](set.md) on a member or an element, `insert` never moves an existing *element's value* -- only where
+`array`'s *links* to its elements live -- so a view of an existing element of `array` stays valid across an
+`insert`, and keeps referring to the same element even though its index shifts. Any iterator already taken over
+`array` is invalidated, since it was walking the old layout. See [Edits](index.md#edits) for what stays valid across
+an edit in general.
+
+## Examples
+
+??? example
+
+    The example below inserts a step into the middle of a deployment plan, without touching the steps that come
+    after it, and shows that a view taken before the insert keeps referring to the same element even though its
+    index shifts -- something a plain `json`/`ordered_json` array, or its `std::vector`-based storage, has no
+    equivalent for.
+
+    ```cpp
+    --8<-- "examples/basic_json_document__insert.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_document__insert.output"
+    ```
+
+## See also
+
+- [push_back](push_back.md) - append to an array
+- [erase](erase.md) - remove an object member, an array element, or the value a JSON pointer refers to
+- [set](set.md) - replace a value, or set an object member, an array element, or the value a JSON pointer refers to
+- [`BasicJsonType::insert`](../basic_json/insert.md) - the corresponding function of `basic_json`
+- [Edits](index.md#edits) - what an edit guarantees, for every overload
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,49 @@
+# <small>nlohmann::basic_json_document::</small>is_discarded
+
+```cpp
+bool is_discarded() const noexcept;
+```
+
+Returns whether the document holds no value, either because it was default-constructed or because the last call to
+[`parse()`](parse.md), [`parse_copy()`](parse_copy.md), or [`read()`](read.md) failed with `allow_exceptions` set to
+`#!cpp false`.
+
+## Return value
+
+`#!cpp true` if the document is discarded, `#!cpp false` otherwise.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Notes
+
+When the document is discarded, [`root()`](root.md) returns a discarded view (its
+[`is_discarded()`](../basic_json_view/is_discarded.md) is also `#!cpp true`).
+
+## Examples
+
+??? example
+
+    ```cpp
+    --8<-- "examples/basic_json_document__is_discarded.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_document__is_discarded.output"
+    ```
+
+## See also
+
+- [parse](parse.md) - deserialize from a compatible input
+- [is_discarded (basic_json_view)](../basic_json_view/is_discarded.md) - return whether a view is invalid
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,169 @@
+# <small>nlohmann::basic_json_document::</small>load
+
+```cpp
+// (1)
+static basic_json_document load(const std::uint8_t* image, std::size_t size,
+                                 const image_check check = image_check::full);
+
+// (2)
+static basic_json_document load(const std::vector<std::uint8_t>& image,
+                                 const image_check check = image_check::full);
+
+// (3)
+static basic_json_document load(std::vector<std::uint8_t>&& image,
+                                 const image_check check = image_check::full);
+```
+
+1. Reads an image [`save()`](save.md) wrote, from a pointer and a byte count. The image is **borrowed**: `image`
+   must stay alive and unchanged for as long as the returned document, and any view taken from it, is used.
+2. Reads an image from a `#!cpp std::vector`. Also **borrowed** -- equivalent to overload 1 called with
+   `#!cpp image.data()` and `#!cpp image.size()`.
+3. Reads an image, keeping the vector instead of copying it: `image` is moved into the document (no copy), which
+   then owns it for as long as it needs the text and the decoded strings. [`owns_source()`](owns_source.md) is
+   `#!cpp true` afterward.
+
+In every overload, the node index is copied into storage the document itself owns -- so that it is properly aligned,
+and, for an [editable](index.md#edits) document, can be edited -- while the text and the decoded strings stay in
+`image`. The hash indexes [large objects](../../features/json_view.md) use for lookup are rebuilt, exactly as after
+parsing.
+
+## Parameters
+
+`image` (in)
+:   the image [`save()`](save.md) wrote (overloads 1 and 2), or one to take ownership of (overload 3)
+
+`size` (in)
+:   the number of bytes at `image` (overload 1)
+
+`check` (in)
+:   how thoroughly to validate `image` before trusting it; see [`image_check`](#image_check) below (optional,
+    `#!cpp image_check::full` by default)
+
+## Return value
+
+The document read from the image.
+
+## Exception safety
+
+Overloads 1 and 2 give the strong guarantee: `image` is only read, never written, so a thrown exception leaves the
+caller's buffer untouched.
+
+Overload 3 moves `image` into the document *before* validating it, so that a good image is kept without a copy. If
+loading then fails, the partially built document -- and the vector now inside it -- is discarded along with the
+exception, and `image` itself is left **empty**, not restored to what was passed in. Move a copy in instead, or
+validate with overload 2 first, if the original vector must survive a failed load.
+
+## Exceptions
+
+On a big-endian target, throws [`type_error.320`](../../home/exceptions.md#jsonexceptiontype_error320) -- the same
+exception [`save()`](save.md#exceptions) throws there, since the image format is little-endian only.
+
+Otherwise throws [`parse_error.116`](../../home/exceptions.md#jsonexceptionparse_error116) if `image` is not one
+`save()` could have written, or fails the requested `check`:
+
+| message               | when                                                                                                |
+|------------------------|------------------------------------------------------------------------------------------------------|
+| `too short`            | `image` is `#!cpp nullptr`, or `size` is smaller than the 64-byte header                             |
+| `unknown format`       | the header's magic bytes or version do not match, or a reserved header field is not zero             |
+| `sizes out of range`   | the node count, text size, or decoded-string size the header describes does not fit `size`, or the `#!cpp '\0'` after the text or after the decoded strings is missing |
+| `the check failed`     | `check` is not `#!cpp image_check::none`, and the image fails it -- see [`image_check`](#image_check) |
+
+!!! failure "Example messages"
+
+    ```
+    [json.exception.parse_error.116] parse error: invalid json_document image: too short
+    ```
+    ```
+    [json.exception.parse_error.116] parse error: invalid json_document image: unknown format
+    ```
+    ```
+    [json.exception.parse_error.116] parse error: invalid json_document image: sizes out of range
+    ```
+    ```
+    [json.exception.parse_error.116] parse error: invalid json_document image: the check failed
+    ```
+
+## Complexity
+
+Linear in the number of nodes, which are always copied into the document. With `#!cpp check == image_check::full`,
+additionally linear in the combined length of the text and the decoded strings; `#!cpp image_check::bounds` and
+`#!cpp image_check::none` do not read them.
+
+## `image_check`
+
+```cpp
+using image_check = detail::view::image_check;
+
+enum class image_check
+{
+    full,
+    bounds,
+    none
+};
+```
+
+How thoroughly `load()` validates `image` before trusting it.
+
+| value    | checks                                                                                                    | guarantees |
+|----------|--------------------------------------------------------------------------------------------------------------|------------|
+| `full`   | everything the parser itself guarantees: structure and bounds; that every string is valid UTF-8 (and, for a string still in the source text, that it contains no quote, backslash, or control character); and that every number token is well-formed and matches the value stored for it | reading and serializing a checked image is safe and always produces valid JSON, exactly as for a parsed document |
+| `bounds` | structure and bounds only -- that every offset and count in the node index stays inside the image            | reading and serializing stay memory-safe, but a crafted image can hold strings that are not valid UTF-8 or that serialize to invalid JSON ([`dump()`](../basic_json_view/dump.md) writes them unchanged or throws [`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316)), and numbers whose values differ from their text |
+| `none`   | nothing                                                                                                       | images from a trusted source only -- reading a damaged image is undefined behavior |
+
+`full` is the default and the right choice for an image from anything you do not fully control -- a file, a cache
+shared with other processes, a peer on the network. `bounds` skips scanning the text and the decoded strings, so it
+fits a cache your own process just wrote and reads straight back, where damage would mean a bug or a hardware fault
+rather than adversarial input; it still cannot crash or read out of bounds. `none` skips validation entirely and
+should only be used for an image you trust as much as your own memory.
+
+## Notes
+
+**Lifetime.** Overloads 1 and 2 borrow `image`: it must stay alive and byte-for-byte unchanged for as long as the
+returned document, and any [view](../basic_json_view/index.md) taken from it, is used -- exactly like a document
+[`parse()`](parse.md) borrowed its input for. Overload 3 avoids this by keeping the vector itself; see
+[`owns_source`](owns_source.md).
+
+!!! warning "Experimental"
+
+    The image format is versioned but not yet stable, and may change in an incompatible way before it is declared
+    stable; `load()` already rejects an image written by a different format version with `parse_error.116`
+    ("unknown format"). Use images to cache a document within one build of the library, or to hand one to another
+    process running the *same* build on the *same* (little-endian) machine -- not as a long-term storage format.
+
+**What `image_check::bounds` does not guarantee.** A bounds-checked image can never make `load()`,
+[`root()`](root.md), element access, or [`materialize()`](../basic_json_view/materialize.md) read outside the image,
+so those stay safe on a damaged one. It does *not* guarantee that the image describes valid JSON: a string
+that a `full` check would have rejected can make [`dump()`](../basic_json_view/dump.md) write invalid UTF-8 or invalid
+JSON, or throw `type_error.316`, and a number can read back with a value that does not match how it is spelled. Reserve `bounds` for images you already trust to be well-formed, and use it
+only to skip the extra scan.
+
+## Examples
+
+??? example "Caching a document, ownership, and a rejected image"
+
+    The example below saves a parsed document as an image, checks that `load()` reproduces the original
+    [`dump()`](../basic_json_view/dump.md) without parsing, and shows the difference between
+    `load(std::move(image))` (owned) and `load(image)` (borrowed). It then damages one byte of the image and shows
+    `image_check::full` rejecting it with `parse_error.116`, while `image_check::bounds` -- meant for a cache the
+    process already trusts -- still reads it without going out of bounds.
+
+    ```cpp
+    --8<-- "examples/basic_json_document__load.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_document__load.output"
+    ```
+
+## See also
+
+- [save](save.md) - write the document as an image
+- [owns_source](owns_source.md) - return whether the document holds its own copy of the text
+- [parse](parse.md) - deserialize from JSON text instead of an image
+- [Images](../../features/json_view.md#images) - why and when to use images
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,50 @@
+# <small>nlohmann::basic_json_document::</small>memory_usage
+
+```cpp
+std::size_t memory_usage() const noexcept;
+```
+
+Returns the number of bytes held by the document: the node index, the decoded-string buffer (for strings that
+contain escapes), and, for an owned document, its copy of the source text.
+
+## Return value
+
+The number of bytes the document holds, `0` for a [discarded](is_discarded.md) document.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Notes
+
+The exact value depends on the platform, the allocator, and the library's own layout, and may change between
+versions; do not rely on it being a specific number, and do not compare it across different builds or platforms.
+Compare it for the same document over time, or between documents built with the same binary, instead -- for instance
+to observe the effect of [`shrink_to_fit()`](shrink_to_fit.md).
+
+## Examples
+
+??? example
+
+    ```cpp
+    --8<-- "examples/basic_json_document__memory_usage.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_document__memory_usage.output"
+    ```
+
+## See also
+
+- [node_count](node_count.md) - the number of index entries
+- [shrink_to_fit](shrink_to_fit.md) - release unused index capacity
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,49 @@
+# <small>nlohmann::basic_json_document::</small>node_count
+
+```cpp
+std::size_t node_count() const noexcept;
+```
+
+Returns the number of entries in the document's flat index.
+
+## Return value
+
+The number of index entries: one per value (of any type, at any nesting depth) plus one per object key. `0` for a
+[discarded](is_discarded.md) document.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Notes
+
+Each index entry is [16 bytes](../../home/architecture.md#node-index-of-json-views), so `#!cpp node_count() * 16` is
+the size of the index itself (part, but not all, of [`memory_usage()`](memory_usage.md), which also counts decoded
+strings and, for an owned document, the text).
+
+## Examples
+
+??? example
+
+    ```cpp
+    --8<-- "examples/basic_json_document__node_count.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_document__node_count.output"
+    ```
+
+## See also
+
+- [memory_usage](memory_usage.md) - the number of bytes held by the document
+- [shrink_to_fit](shrink_to_fit.md) - release unused index capacity
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,49 @@
+# <small>nlohmann::basic_json_document::</small>owns_source
+
+```cpp
+bool owns_source() const noexcept;
+```
+
+Returns whether the document holds its own copy of the parsed text, as opposed to borrowing the caller's buffer.
+
+## Return value
+
+`#!cpp true` if the document owns the text returned by [`source()`](source.md), `#!cpp false` if it borrows it (or if
+the document is [discarded](is_discarded.md)).
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Notes
+
+See the ownership table on [`parse`](parse.md#notes) for which inputs are borrowed and which are owned. A borrowed
+document (`#!cpp owns_source() == false`) is only valid while the buffer it was parsed from is still alive.
+
+## Examples
+
+??? example
+
+    ```cpp
+    --8<-- "examples/basic_json_document__owns_source.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_document__owns_source.output"
+    ```
+
+## See also
+
+- [parse](parse.md) - deserialize from a compatible input
+- [parse_copy](parse_copy.md) - deserialize a copy of a compatible input, always owned
+- [source](source.md) - the parsed text
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,140 @@
+# <small>nlohmann::basic_json_document::</small>parse
+
+```cpp
+// (1)
+template<typename InputType>
+static basic_json_document parse(InputType&& input,
+                                 const bool allow_exceptions = true,
+                                 const bool ignore_comments = false,
+                                 const bool ignore_trailing_commas = false);
+
+// (2)
+template<typename IteratorType>
+static basic_json_document parse(IteratorType first, IteratorType last,
+                                 const bool allow_exceptions = true,
+                                 const bool ignore_comments = false,
+                                 const bool ignore_trailing_commas = false);
+```
+
+1. Deserialize from a compatible input, borrowing or owning it depending on its value category and type (see Notes).
+2. Deserialize from a pair of input iterators.
+
+Both overloads accept exactly what [`BasicJsonType::parse()`](../basic_json/parse.md) accepts, with the same
+`ignore_comments`/`ignore_trailing_commas` options, but build a [`basic_json_document`](index.md) (a flat index into
+the input) instead of a tree of `BasicJsonType` values.
+
+## Template parameters
+
+`InputType`
+:   A compatible input, for instance:
+
+    - a `#!cpp std::string`, `#!cpp std::string_view`, or a C-style array of characters
+    - a pointer to a null-terminated string of single byte characters
+    - a container for which `#!cpp obj.data()` and `#!cpp obj.size()` give contiguous single-byte access, e.g.
+      `#!cpp std::vector<char>` or `#!cpp std::vector<std::uint8_t>`
+    - an `#!cpp std::istream` object, or anything else [`BasicJsonType::parse()`](../basic_json/parse.md) accepts
+
+`IteratorType`
+:   a compatible iterator type, for instance a pair of pointers such as `ptr` and `ptr + len`, or a pair of
+    `#!cpp std::string::iterator`
+
+## Parameters
+
+`input` (in)
+:   Input to parse from.
+
+`allow_exceptions` (in)
+:   whether to throw exceptions in case of a parse error (optional, `#!cpp true` by default)
+
+`ignore_comments` (in)
+:   whether comments should be ignored and treated like whitespace (`#!cpp true`) or yield a parse error
+    (`#!cpp false`); (optional, `#!cpp false` by default)
+
+`ignore_trailing_commas` (in)
+:   whether trailing commas in arrays or objects should be ignored and treated like whitespace (`#!cpp true`) or
+    yield a parse error (`#!cpp false`); (optional, `#!cpp false` by default)
+
+`first` (in)
+:   iterator to the start of a character range
+
+`last` (in)
+:   iterator to the end of a character range
+
+## Return value
+
+The parsed document. If `allow_exceptions` is `#!cpp false` and the input is not valid JSON, the returned document is
+discarded; see [`is_discarded`](is_discarded.md).
+
+## Exceptions
+
+Throws the same exception [`BasicJsonType::parse()`](../basic_json/parse.md) throws for the same input and options --
+the same exception id, message, and position -- because on a failing input the library's own parser is run on the
+same bytes to produce the diagnostic. Additionally throws
+[`out_of_range.416`](../../home/exceptions.md#jsonexceptionout_of_range416) if the input is 4 GiB or larger, a size
+[`BasicJsonType::parse()`](../basic_json/parse.md) does not reject.
+
+## Complexity
+
+Linear in the length of the input.
+
+## Notes
+
+**Ownership.** Whether the document borrows `input` or owns a copy of it depends on its value category and type:
+
+| `input`                                                                             | ownership                                                    |
+|--------------------------------------------------------------------------------------|--------------------------------------------------------------|
+| lvalue byte container (`std::string`, `std::vector<char>`, ...), `std::string_view`, C string, character array | **borrowed** -- `input` must outlive the document |
+| rvalue `#!cpp std::string`                                                            | **owned**, moved in without a copy                            |
+| rvalue byte container other than `#!cpp std::string`                                  | **owned**, copied                                             |
+| stream, wide string, or anything else read through the general input adapter          | **owned**, read into a buffer (a stream is read to its end)   |
+
+For overload (2), a pair of pointers to single-byte integers (e.g. `#!cpp const char*`, `#!cpp std::uint8_t*`) is
+borrowed. From C++20 on, so is any other contiguous iterator over single bytes, such as
+`#!cpp std::vector<char>::iterator` or `#!cpp std::string::const_iterator`. Before C++20 these iterators cannot be
+told apart from other class-type iterators, so their range is read into an owned buffer, as is any non-contiguous
+range (e.g. of a `#!cpp std::list<char>`).
+
+See [`owns_source`](owns_source.md) to check which happened after a call, and the
+[feature page](../../features/json_view.md) for the reasoning.
+
+**Numbers.** As for [`BasicJsonType::parse()`](../basic_json/parse.md), an integer literal too large for the 64-bit
+integer type becomes a floating-point value.
+
+## Examples
+
+??? example "Example: (1) borrowed vs. owned input, and errors identical to `BasicJsonType::parse()`"
+
+    ```cpp
+    --8<-- "examples/basic_json_document__parse.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_document__parse.output"
+    ```
+
+??? example "Example: (2) parse an iterator range (no NUL terminator required)"
+
+    ```cpp
+    --8<-- "examples/basic_json_document__parse_iterator_pair.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_document__parse_iterator_pair.output"
+    ```
+
+## See also
+
+- [parse_copy](parse_copy.md) - deserialize a copy of a compatible input
+- [accept](accept.md) - check whether the input is valid JSON
+- [read](read.md) - (re-)parse into this document, reusing its memory
+- [owns_source](owns_source.md) - return whether the document holds its own copy of the text
+- [load](load.md) - read a document from an image instead of parsing JSON text
+- [`BasicJsonType::parse`](../basic_json/parse.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,77 @@
+# <small>nlohmann::basic_json_document::</small>parse_copy
+
+```cpp
+template<typename InputType>
+static basic_json_document parse_copy(InputType&& input,
+                                      const bool allow_exceptions = true,
+                                      const bool ignore_comments = false,
+                                      const bool ignore_trailing_commas = false);
+```
+
+Deserialize from a compatible input, always taking the document's own copy of it, regardless of the value category or
+type of `input`. Unlike [`parse()`](parse.md), the returned document never depends on `input` staying alive.
+
+## Template parameters
+
+`InputType`
+:   A compatible input; see [`parse`](parse.md#template-parameters).
+
+## Parameters
+
+`input` (in)
+:   Input to parse from.
+
+`allow_exceptions` (in)
+:   whether to throw exceptions in case of a parse error (optional, `#!cpp true` by default)
+
+`ignore_comments` (in)
+:   whether comments should be ignored and treated like whitespace (`#!cpp true`) or yield a parse error
+    (`#!cpp false`); (optional, `#!cpp false` by default)
+
+`ignore_trailing_commas` (in)
+:   whether trailing commas in arrays or objects should be ignored and treated like whitespace (`#!cpp true`) or
+    yield a parse error (`#!cpp false`); (optional, `#!cpp false` by default)
+
+## Return value
+
+The parsed document, with [`owns_source()`](owns_source.md) `#!cpp true`. If `allow_exceptions` is `#!cpp false` and
+the input is not valid JSON, the returned document is discarded; see [`is_discarded`](is_discarded.md).
+
+## Exceptions
+
+Same as [`parse`](parse.md#exceptions).
+
+## Complexity
+
+Linear in the length of the input.
+
+## Notes
+
+`parse_copy()` accepts and rejects exactly what [`parse()`](parse.md) does, and classifies numbers the same way; it
+only differs in that the input is always copied rather than sometimes borrowed. Prefer [`parse()`](parse.md) when the
+input's lifetime already covers the document's, since it avoids the copy for borrowed inputs.
+
+## Examples
+
+??? example
+
+    The example below returns a document from a function whose local buffer would otherwise not outlive it.
+
+    ```cpp
+    --8<-- "examples/basic_json_document__parse_copy.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_document__parse_copy.output"
+    ```
+
+## See also
+
+- [parse](parse.md) - deserialize from a compatible input, borrowing it where possible
+- [owns_source](owns_source.md) - return whether the document holds its own copy of the text
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,102 @@
+# <small>nlohmann::basic_json_document::</small>push_back
+
+```cpp
+template<typename V>
+view_type push_back(view_type array, V&& value);
+```
+
+Appends `value` as a new last element of `array`. A [null](../basic_json_view/is_null.md) `array` first becomes an
+empty array, the same way [`set`](set.md) turns a null `object` into an empty object.
+
+`value` is accepted three ways: a [`basic_json_view`](../basic_json_view/index.md) of *any* document -- read-only or
+editable, and it does not have to be `array`'s own document -- which is copied so that nothing is shared with the
+source document afterward; a `BasicJsonType` value; or anything `BasicJsonType` can be constructed from (numbers,
+strings, `#!cpp bool`, `#!cpp nullptr`, containers, ...).
+
+Only an **editable** document (`#!cpp Editable == true`, e.g. [`json_editable_document`](../json_editable_document.md))
+has `push_back`; calling it on a read-only `basic_json_document` fails to compile (`#!cpp static_assert`).
+
+## Template parameters
+
+`V`
+:   the type of `value`, deduced; see above for what is accepted.
+
+## Parameters
+
+`array` (in)
+:   the array (or null value) to append to
+
+`value` (in)
+:   the value to append
+
+## Return value
+
+a view of the new last element of `array`, now holding `value`
+
+## Exception safety
+
+Basic exception safety: `value` is fully encoded -- including the checks below -- into storage owned by the document
+before anything already reachable from [`root()`](root.md) is touched, so a failure while encoding `value` (an
+invalid argument, or `#!cpp std::bad_alloc`) leaves the document completely unchanged, other than memory allocated
+for the encoding that is not reclaimed. A failure of a later allocation -- while `array` switches from its parsed
+layout to a growable block, or while that block grows, see [Notes](#notes) -- can still leave a partial effect, such
+as a null `array` argument already turned into an empty array even though `value` itself was not appended.
+
+## Exceptions
+
+Throws [`type_error.308`](../../home/exceptions.md#jsonexceptiontype_error308) if `array` is neither an array nor
+null -- the same message [`BasicJsonType::push_back`](../basic_json/push_back.md) throws for the same type. Throws
+[`invalid_iterator.202`](../../home/exceptions.md#jsonexceptioninvalid_iterator202) ("view does not belong to this
+document") if `array` is a [discarded](../basic_json_view/is_discarded.md) view or a view of a *different* document.
+Throws [`type_error.302`](../../home/exceptions.md#jsonexceptiontype_error302) if `value` is a
+[discarded](../basic_json_view/is_discarded.md) view or a [discarded](../basic_json/is_discarded.md) `BasicJsonType`
+value, and [`type_error.319`](../../home/exceptions.md#jsonexceptiontype_error319) if `value` is (or contains) a
+binary value -- `BasicJsonType` can hold one, but a `json_document` cannot. Throws
+[`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316) if `value` is (or contains) a string that is
+not valid UTF-8, with the same message [`BasicJsonType::dump()`](../basic_json/dump.md) gives for that string.
+
+## Complexity
+
+Amortized constant, plus time linear in the size of `value` to encode it into the document's storage (constant for
+a scalar, linear in the number of nested values for an array or object): the elements of `array` move to a growable
+block of links the first time it is appended to (or [`set`](set.md) on), and that block itself grows -- doubling its
+capacity, so the cost of growing it amortizes to constant per element -- only once it runs out of room. See
+[Notes](#notes).
+
+## Notes
+
+Like [`set`](set.md) on a member or an element, `push_back` never moves an existing element itself -- only where
+`array`'s *links* to its elements live -- so a view of an existing element of `array` stays valid across a
+`push_back`, but any iterator already taken over `array` is invalidated, since it was walking the old layout. See
+[Edits](index.md#edits) for what stays valid across an edit in general.
+
+## Examples
+
+??? example
+
+    The example below appends records to an array one at a time, as they might arrive from a stream of events,
+    without ever building a `BasicJsonType` value for the array or for the records already in it, and shows that a
+    view taken from an earlier `push_back` still refers to the same element once later ones have run.
+
+    ```cpp
+    --8<-- "examples/basic_json_document__push_back.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_document__push_back.output"
+    ```
+
+## See also
+
+- [set](set.md) - replace a value, or set an object member, an array element, or the value a JSON pointer refers to
+- [insert](insert.md) - insert an element into an array before a given position
+- [erase](erase.md) - remove an object member, an array element, or the value a JSON pointer refers to
+- [root](root.md) - the view of the root value
+- [`BasicJsonType::push_back`](../basic_json/push_back.md) - the corresponding function of `basic_json`
+- [Edits](index.md#edits) - what an edit guarantees, for every overload
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,77 @@
+# <small>nlohmann::basic_json_document::</small>read
+
+```cpp
+template<typename InputType>
+void read(InputType&& input,
+         const bool allow_exceptions = true,
+         const bool ignore_comments = false,
+         const bool ignore_trailing_commas = false);
+```
+
+(Re-)parses `input` into `#!cpp *this`, discarding the document's previous value and reusing its memory (the node
+index, the decoded-string buffer, and, if applicable, the owned copy of the text) rather than allocating a fresh
+document. [`parse()`](parse.md) is implemented in terms of this function, applied to a default-constructed document.
+
+## Template parameters
+
+`InputType`
+:   A compatible input; see [`parse`](parse.md#template-parameters).
+
+## Parameters
+
+`input` (in)
+:   Input to parse from.
+
+`allow_exceptions` (in)
+:   whether to throw exceptions in case of a parse error (optional, `#!cpp true` by default)
+
+`ignore_comments` (in)
+:   whether comments should be ignored and treated like whitespace (`#!cpp true`) or yield a parse error
+    (`#!cpp false`); (optional, `#!cpp false` by default)
+
+`ignore_trailing_commas` (in)
+:   whether trailing commas in arrays or objects should be ignored and treated like whitespace (`#!cpp true`) or
+    yield a parse error (`#!cpp false`); (optional, `#!cpp false` by default)
+
+## Exceptions
+
+Same as [`parse`](parse.md#exceptions).
+
+## Complexity
+
+Linear in the length of the input.
+
+## Notes
+
+Every view taken from `#!cpp *this` before the call -- including the previous [`root()`](root.md) -- is invalidated,
+whether or not the new parse succeeds; take fresh views from [`root()`](root.md) afterward.
+
+`input` is borrowed or owned by the same rules as [`parse()`](parse.md#notes); a document can borrow on one call and
+own on the next, since ownership is decided freshly each time.
+
+## Examples
+
+??? example
+
+    The example below parses a sequence of messages into the same document, reusing its memory instead of allocating
+    a new document for each one.
+
+    ```cpp
+    --8<-- "examples/basic_json_document__read.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_document__read.output"
+    ```
+
+## See also
+
+- [parse](parse.md) - deserialize from a compatible input
+- [root](root.md) - the view of the root value
+- [load](load.md) - read a document from an image instead of parsing JSON text
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,50 @@
+# <small>nlohmann::basic_json_document::</small>root
+
+```cpp
+view_type root() const noexcept;
+```
+
+Returns a view of the root value of the document.
+
+## Return value
+
+A [`view_type`](index.md#member-types) (i.e. `#!cpp basic_json_view<BasicJsonType>`) for the root value, or a
+discarded view if the document is [discarded](is_discarded.md).
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Notes
+
+`root()` is a cheap handle into the document's index, not a copy of anything; call it as often as needed. The
+returned view is valid under the same conditions as any other view of the document -- see
+[Object inspection](../basic_json_view/index.md) -- in particular, it is invalidated by the next
+[`read()`](read.md) or [`shrink_to_fit()`](shrink_to_fit.md) on this document.
+
+## Examples
+
+??? example
+
+    ```cpp
+    --8<-- "examples/basic_json_document__root.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_document__root.output"
+    ```
+
+## See also
+
+- [is_discarded](is_discarded.md) - return whether the last parse failed
+- [materialize](../basic_json_view/materialize.md) - build the `BasicJsonType` value of a subtree
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,104 @@
+# <small>nlohmann::basic_json_document::</small>save
+
+```cpp
+std::vector<std::uint8_t> save() const;
+```
+
+Writes the document as an *image*: a byte buffer that [`load`](load.md) reads back without parsing. The image holds
+the node index, the source text (plus, for an edited document, the number tokens edits wrote), and the decoded
+strings (plus the strings edits wrote) -- everything [`root()`](root.md) needs, with nothing left to parse.
+
+An edited document is written in its *current* state, with its values in document order, the way the library's own
+parser would have produced them for that JSON text: a member [`set`](set.md) added goes at the end, an
+[`erase`](erase.md)d member leaves no trace, and a float that is not finite (NaN or positive/negative infinity)
+becomes null, the same substitution [`dump()`](../basic_json_view/dump.md) makes. The same document always saves to
+the same bytes -- also across `BasicJsonType` and `#!cpp Editable`, since the image reflects document order and
+values only, not which specialization produced them.
+
+## Return value
+
+The image, as a `#!cpp std::vector<std::uint8_t>`. Pass it, or a pointer to its data together with its size, to
+[`load`](load.md) to read the document back.
+
+## Exception safety
+
+Strong guarantee: `save()` does not modify `#!cpp *this` (it is `#!cpp const`), so if it throws, the document is left
+exactly as it was, and the partially built image is discarded with the exception.
+
+## Exceptions
+
+Throws [`type_error.320`](../../home/exceptions.md#jsonexceptiontype_error320) if the document is
+[discarded](is_discarded.md) -- a default-constructed document, or one a failed [`parse()`](parse.md)/
+[`read()`](read.md) with `allow_exceptions == false` left discarded.
+
+On a big-endian target, throws `type_error.320` with a different message instead: the image format is little-endian
+only (see [Notes](#notes)).
+
+Throws [`out_of_range.416`](../../home/exceptions.md#jsonexceptionout_of_range416) if the node count, the text, or
+the decoded strings of the image would individually reach 4 GiB -- the same 32-bit offsets
+[`parse()`](parse.md#exceptions) and, for edits, [`set`](set.md)/[`push_back`](push_back.md) are already limited to.
+
+!!! failure "Example messages"
+
+    ```
+    [json.exception.type_error.320] cannot save a discarded json_document
+    ```
+    ```
+    [json.exception.type_error.320] json_document images need a little-endian target
+    ```
+    ```
+    [json.exception.out_of_range.416] images of 4 GiB or more are not supported by json_document
+    ```
+
+## Complexity
+
+Linear in the size of the document: the number of nodes, plus the length of the text and the decoded strings that end
+up in the image.
+
+## Notes
+
+**Format.** The image begins with a 64-byte header (the magic bytes `#!cpp "NJVI"`, a version number, the node count,
+and the sizes of the text and the decoded strings, all little-endian), followed by the nodes
+([16 bytes each](../../home/architecture.md#node-index-of-json-views)), the text and a `#!cpp '\0'`, and the decoded
+strings and a `#!cpp '\0'`. [`load`](load.md) checks the header, and the sizes it describes, before reading anything
+else -- see [`load`'s Exceptions](load.md#exceptions).
+
+!!! warning "Experimental"
+
+    The image format is versioned but not yet stable: it may change in an incompatible way before it is declared
+    stable. Use images to cache a document within one build of the library, or to hand one to another process running
+    the *same* build on the *same* (little-endian) machine -- not as a long-term storage format. Keep the original
+    JSON text if you need to read a saved document back with a future library version.
+
+**Little-endian only.** The image is written as raw little-endian bytes, with no byte-swapping. `save()` (and
+[`load`](load.md)) throw `type_error.320` on a big-endian target rather than silently produce bytes a big-endian
+reader could not interpret correctly.
+
+## Examples
+
+??? example "Caching a parsed document as an image"
+
+    The example below saves a parsed configuration as an image -- the way a service might cache one to answer later
+    requests without parsing the text again -- and confirms that loading it back gives exactly the same result as
+    parsing did, and that saving is deterministic.
+
+    ```cpp
+    --8<-- "examples/basic_json_document__save.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_document__save.output"
+    ```
+
+## See also
+
+- [load](load.md) - read an image written by `save()`
+- [owns_source](owns_source.md) - return whether the document holds its own copy of the text
+- [`basic_json_view::dump`](../basic_json_view/dump.md) - serialize the document to JSON text instead of an image
+- [Images](../../features/json_view.md#images) - why and when to use images
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,194 @@
+# <small>nlohmann::basic_json_document::</small>set
+
+```cpp
+// (1)
+template<typename V>
+view_type set(view_type target, V&& value);
+
+// (2)
+template<typename V>
+view_type set(view_type object, string_view_t key, V&& value);
+
+// (3)
+template<typename I, typename V>
+view_type set(view_type array, I idx, V&& value);
+
+// (4)
+template<typename V>
+view_type set(const json_pointer& ptr, V&& value);
+```
+
+Only an **editable** document (`#!cpp Editable == true`, e.g. [`json_editable_document`](../json_editable_document.md))
+has `set`; calling it on a read-only `basic_json_document` fails to compile (`#!cpp static_assert`).
+
+1. Replaces the value `target` refers to with `value`.
+2. Sets the member `key` of the object `object` to `value`: assigns it if `object` already has a member with this
+   key -- the first one, should the key occur more than once, and the later duplicates are then dropped (see the
+   [Notes](#notes) below) -- or appends a new member at the end otherwise. A [null](../basic_json_view/is_null.md)
+   `object` first becomes an empty object.
+3. Assigns `value` to the element at index `idx` of the array `array`, which must already exist (`#!cpp idx <
+   array.size()`).
+4. Sets the value the JSON pointer `ptr` refers to, relative to [`root()`](root.md), to `value`. The *parent* of the
+   target must already exist: an object member is set as in 2. (added if it does not exist yet), an array element is
+   assigned as in 3., and a last reference token of `#!cpp "-"`, or equal to the size of the array, appends `value`
+   instead, exactly as [`push_back`](push_back.md) would. An empty `ptr` sets [`root()`](root.md) itself, as in 1.
+
+In every overload, `value` is accepted three ways: a [`basic_json_view`](../basic_json_view/index.md) of *any*
+document -- read-only or editable, and it does not have to be `target`'s/`object`'s/`array`'s own document -- which
+is copied so that nothing is shared with the source document afterward; a `BasicJsonType` value; or anything
+`BasicJsonType` can be constructed from (numbers, strings, `#!cpp bool`, `#!cpp nullptr`, containers, ...).
+
+## Template parameters
+
+`V`
+:   the type of `value`, deduced; see above for what is accepted.
+
+`I`
+:   an integral type other than `#!cpp bool`, deduced (overloads taking a `#!cpp bool` or a non-integral type for
+    `idx` do not participate in overload resolution).
+
+## Parameters
+
+`target` (in)
+:   the value to replace
+
+`object` (in)
+:   the object (or null value) whose member to set
+
+`array` (in)
+:   the array whose element to assign
+
+`key` (in)
+:   the key of the member to set
+
+`idx` (in)
+:   the index of the element to assign; a negative value throws (see [Exceptions](#exceptions))
+
+`ptr` (in)
+:   a JSON pointer to the value to set, relative to `root()`
+
+`value` (in)
+:   the new value
+
+## Return value
+
+1. a view of `target`, now holding `value`
+2. a view of the member `key` of `object`, now holding `value`
+3. a view of the element `idx` of `array`, now holding `value`
+4. a view of the value `ptr` refers to, now holding `value`
+
+## Exception safety
+
+Basic exception safety: `value` is fully encoded -- including the checks below -- into storage owned by the document
+before anything already reachable from [`root()`](root.md) is touched, so a failure while encoding `value` (an
+invalid argument, or `#!cpp std::bad_alloc`) leaves the document completely unchanged, other than memory allocated
+for the encoding that is not reclaimed. A failure of a later allocation -- while an edited array or object switches
+from its parsed layout to a growable block, see [Notes](#notes) -- can still leave a partial effect, such as a
+[null](../basic_json_view/is_null.md) `object`/`array` argument already turned into an empty object/array even
+though `value` itself was not linked in.
+
+## Exceptions
+
+1. Throws [`type_error.302`](../../home/exceptions.md#jsonexceptiontype_error302) if `value` is a
+   [discarded](../basic_json_view/is_discarded.md) view, or a [discarded](../basic_json/is_discarded.md)
+   `BasicJsonType` value (e.g. `#!cpp BasicJsonType(value_t::discarded)`) -- an object or array `value`, of either
+   kind, is fine and is encoded as a whole subtree.
+2. Throws [`type_error.305`](../../home/exceptions.md#jsonexceptiontype_error305) if `object` is neither an object
+   nor null -- the same message [`operator[]`](../basic_json_view/operator%5B%5D.md) throws for a string argument on
+   such a value. Throws [`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316) if `key` is not
+   valid UTF-8, with the same message [`BasicJsonType::dump()`](../basic_json/dump.md) gives for that string.
+   Also throws what 1. throws for `value`.
+3. Throws `type_error.305` if `array` is not an array -- the same message `operator[]` throws for a numeric argument
+   on such a value. Throws [`out_of_range.401`](../../home/exceptions.md#jsonexceptionout_of_range401) if `idx` is
+   negative, or if `#!cpp idx >= array.size()`. Also throws what 1. throws for `value`.
+4. Throws what [`at`](../basic_json_view/at.md) throws (overload 3) for resolving `ptr`'s parent, except that a
+   missing object member or an array index equal to the array's size at the very last reference token is not an
+   error there (it becomes a new member or an appended element) instead of
+   [`out_of_range.403`](../../home/exceptions.md#jsonexceptionout_of_range403)/[`out_of_range.402`](../../home/exceptions.md#jsonexceptionout_of_range402).
+   For the last reference token itself: if the parent is an object (or a primitive value, where it throws
+   `type_error.305`), throws what 2. throws; if the parent is an array, throws what 3. throws for an index that is
+   out of range, or, for a token that is not a valid array index,
+   [`parse_error.106`](../../home/exceptions.md#jsonexceptionparse_error106) (a leading `#!cpp '0'`),
+   [`parse_error.109`](../../home/exceptions.md#jsonexceptionparse_error109) (not a number),
+   [`out_of_range.410`](../../home/exceptions.md#jsonexceptionout_of_range410) (too large for `size_type`), or
+   [`out_of_range.404`](../../home/exceptions.md#jsonexceptionout_of_range404) (an empty token). Also throws what 1.
+   throws for `value`.
+
+Every overload also throws [`type_error.319`](../../home/exceptions.md#jsonexceptiontype_error319) if `value` is (or
+contains) a binary value -- `BasicJsonType` can hold one, but a `json_document` cannot -- and
+[`invalid_iterator.202`](../../home/exceptions.md#jsonexceptioninvalid_iterator202) ("view does not belong to this
+document") if `target`/`object`/`array` is a [discarded](../basic_json_view/is_discarded.md) view or a view of a
+*different* document (overloads 1-3 only; overload 4 always starts from this document's own [`root()`](root.md)).
+
+## Complexity
+
+1. Linear in the size of `value` (encoding it into the document's storage): constant for a scalar, linear in the
+   number of nested values for an array or object. If `target` is itself an array or object that spans more than one
+   node in its parent's original, unedited layout, and `value` is a scalar, replacing it additionally costs time
+   linear in the number of elements of that parent, the *first* time -- see [Notes](#notes).
+2. Linear in the number of members of `object`, to find an existing member with `key`, plus the complexity of 1. for
+   `value`.
+3. Constant, plus the complexity of 1. for `value`.
+4. Linear in the number of reference tokens of `ptr` and, for each token, in the number of members of the object at
+   that level or the index into the array (as [`at`](../basic_json_view/at.md)), plus the complexity of 2. or 3. for
+   the last token.
+
+## Notes
+
+!!! info "Duplicate keys"
+
+    If `object` already has more than one member with `key` (2.), the *first* one is assigned `value` and every
+    later member with the same key is removed -- so that a lookup, an iteration, and
+    [`materialize()`](../basic_json_view/materialize.md) of `object` afterward all agree on a single value for
+    `key`, the same way [`operator[]`](../basic_json_view/operator%5B%5D.md) already picks the first occurrence of a
+    duplicate key for reading. See the [Notes on duplicate keys](../basic_json_view/operator%5B%5D.md#notes) of
+    `operator[]`.
+
+Setting a member (2.) or an element (3., through 4.) of an array or object whose elements have not been edited
+before switches it from its parsed layout to a growable block holding links to its elements; a later
+[`push_back`](push_back.md) or `set` on the same container reuses that block, growing it (amortized constant time)
+only once it runs out of room. This never moves an element itself -- only where the container's *links* to its
+elements live -- so a view of an element stays valid, but any iterator already taken over the container is
+invalidated, since it was walking the old layout. See [Edits](index.md#edits) for what stays valid across an edit in
+general.
+
+The same switch happens, for the same reason, when overload 1. replaces a multi-node array/object value with a
+scalar: the *parent's* element sequence is what has to switch to links, not `target` itself, because the parent
+originally stepped over `target`'s whole subtree by its node count, which no longer applies once `target` is a
+one-node scalar.
+
+## Examples
+
+??? example "Example: (1)/(2)/(3)/(4) replace a value, set a member, assign an element, set via a JSON pointer"
+
+    The example below edits a small configuration document -- replacing a value, adding an object member, assigning
+    an array element, and reaching a field through a JSON pointer -- and shows what
+    [`dump()`](../basic_json_view/dump.md) preserves that is lost once the same edits are made on a `BasicJsonType`
+    value instead: the order object members were written in, and the exact spelling of a number that was never
+    touched.
+
+    ```cpp
+    --8<-- "examples/basic_json_document__set.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_document__set.output"
+    ```
+
+## See also
+
+- [push_back](push_back.md) - append to an array
+- [insert](insert.md) - insert an element into an array
+- [erase](erase.md) - remove an object member, an array element, or the value a JSON pointer refers to
+- [root](root.md) - the view of the root value, the starting point of overload 4
+- [`basic_json_view::dump`](../basic_json_view/dump.md) - serialize the document, keeping an untouched number's
+  spelling with `#!cpp number_format::source`
+- [Edits](index.md#edits) - what an edit guarantees, for every overload
+- [Editing a document](../../features/json_view.md#editing-a-document) - why editable documents keep the source
+  text's order and number spelling
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,58 @@
+# <small>nlohmann::basic_json_document::</small>shrink_to_fit
+
+```cpp
+void shrink_to_fit();
+```
+
+Releases capacity that is no longer needed, both of the node index and of the buffer for decoded strings (strings that
+contained escape sequences), e.g. after [`read()`](read.md) replaced a large document with a much smaller one. Like
+`#!cpp std::vector::shrink_to_fit()`, this is a non-binding request: the library may keep more capacity than strictly
+necessary.
+
+## Exception safety
+
+Strong guarantee: if an exception is thrown, there are no changes to the document.
+
+## Exceptions
+
+May throw `#!cpp std::bad_alloc` if the reallocation fails; on exception, the document is unchanged.
+
+## Complexity
+
+Linear in [`node_count()`](node_count.md) plus the length of the decoded strings.
+
+## Notes
+
+!!! warning "Invalidates views"
+
+    Unlike moving the document, `shrink_to_fit()` **invalidates every view taken from this document before the
+    call**, including a previously obtained [`root()`](root.md): the node index is moved into a new, smaller
+    allocation, and the old one is freed. Take a fresh view from [`root()`](root.md) after calling this function.
+
+This is unlike `#!cpp std::vector::shrink_to_fit()`, which promises nothing about validity but in practice often
+leaves iterators alone when it did not need to reallocate; here, an implementation that avoids a reallocation when
+possible would be an internal optimization only, not a guarantee to rely on.
+
+## Examples
+
+??? example
+
+    ```cpp
+    --8<-- "examples/basic_json_document__shrink_to_fit.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_document__shrink_to_fit.output"
+    ```
+
+## See also
+
+- [node_count](node_count.md) - the number of index entries
+- [memory_usage](memory_usage.md) - the number of bytes held by the document
+- [root](root.md) - the view of the root value
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,48 @@
+# <small>nlohmann::basic_json_document::</small>source
+
+```cpp
+view_type::string_view_t source() const noexcept;
+```
+
+Returns the parsed text, whether it is borrowed from the caller or owned by the document.
+
+## Return value
+
+A `#!cpp string_view_t` (`#!cpp std::string_view` on C++17 and newer) over the parsed text, or an empty one if the
+document is [discarded](is_discarded.md).
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Notes
+
+For a borrowed document, `source()` points directly into the caller's buffer, so it is only valid while that buffer
+is; see [`owns_source`](owns_source.md).
+
+## Examples
+
+??? example
+
+    ```cpp
+    --8<-- "examples/basic_json_document__source.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_document__source.output"
+    ```
+
+## See also
+
+- [owns_source](owns_source.md) - return whether the document holds its own copy of the text
+- [source_offset](../basic_json_view/source_offset.md) - byte offset of a value in the source text
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,134 @@
+# <small>nlohmann::basic_json_view::</small>at
+
+```cpp
+// (1)
+basic_json_view at(string_view_t key) const;
+basic_json_view at(const char* key) const;
+basic_json_view at(const string_t& key) const;
+
+// (2)
+basic_json_view at(size_type idx) const;
+basic_json_view at(int idx) const;
+
+// (3)
+basic_json_view at(const json_pointer& ptr) const;
+```
+
+1. Returns the value of the object member with key `key` -- the first one, should the key occur more than once (see
+   [Notes on duplicate keys](operator[].md#notes)).
+2. Returns the array element at index `idx`.
+3. Returns the value a JSON pointer `ptr` refers to, starting at this value.
+
+## Parameters
+
+`key` (in)
+:   object key of the element to access
+
+`idx` (in)
+:   index of the element to access
+
+`ptr` (in)
+:   JSON pointer to the element to access
+
+## Return value
+
+1. the value of the first member with key `key`
+2. the element at index `idx`
+3. the value `ptr` resolves to, starting at this value
+
+## Exception safety
+
+Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
+
+## Exceptions
+
+1. The function can throw the following exceptions, both with the same message as the corresponding call to
+   [`BasicJsonType::at`](../basic_json/at.md):
+    - Throws [`type_error.304`](../../home/exceptions.md#jsonexceptiontype_error304) if the value is not an object.
+    - Throws [`out_of_range.403`](../../home/exceptions.md#jsonexceptionout_of_range403) if no member has key `key`.
+2. The function can throw the following exceptions, both with the same message as the corresponding call to
+   [`BasicJsonType::at`](../basic_json/at.md):
+    - Throws [`type_error.304`](../../home/exceptions.md#jsonexceptiontype_error304) if the value is not an array.
+    - Throws [`out_of_range.401`](../../home/exceptions.md#jsonexceptionout_of_range401) if `#!cpp idx >= size()`.
+3. The function can throw the following exceptions, all with the same message as the corresponding call to
+   [`BasicJsonType::at`](../basic_json/at.md):
+    - Throws [`parse_error.106`](../../home/exceptions.md#jsonexceptionparse_error106) if an array index in `ptr`
+      begins with `#!cpp '0'`.
+    - Throws [`parse_error.109`](../../home/exceptions.md#jsonexceptionparse_error109) if an array index in `ptr` is
+      not a number.
+    - Throws [`out_of_range.401`](../../home/exceptions.md#jsonexceptionout_of_range401) if an array index in `ptr`
+      is out of range.
+    - Throws [`out_of_range.402`](../../home/exceptions.md#jsonexceptionout_of_range402) if a reference token is
+      `#!cpp "-"` at an array -- `at` never inserts an element, so `#!cpp "-"` is always invalid.
+    - Throws [`out_of_range.403`](../../home/exceptions.md#jsonexceptionout_of_range403) if a reference token names
+      an object member that does not exist.
+    - Throws [`out_of_range.404`](../../home/exceptions.md#jsonexceptionout_of_range404) if `ptr` cannot be resolved
+      because a reference token is used on a primitive value.
+
+None of these exceptions carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) path: the view has no
+`BasicJsonType` value to point at, so the exception is created without one, even if `BasicJsonType` was built with
+`JSON_DIAGNOSTICS` enabled.
+
+## Complexity
+
+1. Linear in the number of members: as for [`ordered_json`](../ordered_json.md), members are compared one after
+   another, in document order, stopping at the first match. Each comparison first checks the key's length --
+   already known from the index, without reading the key bytes -- before comparing its content.
+   Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time
+   on average.
+2. Linear in `idx`: elements are skipped one at a time from the first one, since they are not a fixed size in the
+   index (unlike `BasicJsonType`'s array, which is random-access).
+3. Linear in the number of reference tokens of `ptr` and, for each token, in the number of members of the object at
+   that level (as 1.) or the index into the array (as 2.).
+
+## Notes
+
+Unlike [`operator[]`](operator[].md), which returns a [discarded](is_discarded.md) view for a missing key or an
+out-of-range index, `at` always throws -- exactly as `BasicJsonType::at` does, and with the same messages, so
+existing error handling written against `BasicJsonType::at` keeps working unchanged when switched to a view. This
+also holds for overload 3: unlike [`operator[]`](operator[].md) with a JSON pointer, which returns a discarded view
+for a missing key or an out-of-range index, `at` throws for those too (`out_of_range.403`/`out_of_range.401`).
+
+## Examples
+
+??? example "Example: (1)/(2) access specified element with bounds checking"
+
+    The example below reads required fields out of a service configuration with `at`, and shows that the exceptions
+    it throws -- for a wrong type and for a missing key -- carry the same messages
+    [`BasicJsonType::at`](../basic_json/at.md) would produce for the same JSON text.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__at.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__at.output"
+    ```
+
+??? example "Example: (3) access specified element via JSON pointer with bounds checking"
+
+    The example below shows that `at` with a JSON pointer throws exactly the exceptions, with exactly the messages,
+    that [`BasicJsonType::at`](../basic_json/at.md) throws for the same pointer and the same document.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__at_json_pointer.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__at_json_pointer.output"
+    ```
+
+## See also
+
+- [operator[]](operator[].md) - access specified element (returns a discarded view instead of throwing)
+- [front](front.md), [back](back.md) - access the first or last element
+- [`BasicJsonType::at`](../basic_json/at.md) - the corresponding function of `basic_json`
+- [`json_pointer`](../json_pointer/index.md) - JSON pointer type used by overload 3
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,64 @@
+# <small>nlohmann::basic_json_view::</small>back
+
+```cpp
+basic_json_view back() const;
+```
+
+Returns the last element of an array, the last member value of an object, or the value itself if it is primitive
+(as for [`BasicJsonType::back()`](../basic_json/back.md), a primitive value is a range of one element).
+
+## Return value
+
+The last element or member value. For a primitive value (number, string, boolean), the value itself.
+
+## Exception safety
+
+Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
+
+## Exceptions
+
+Throws [`invalid_iterator.214`](../../home/exceptions.md#jsonexceptioninvalid_iterator214) if the view is
+[null](is_null.md) or [discarded](is_discarded.md), or if it is an empty array or object.
+
+This exception does not carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) path: the view has no
+`BasicJsonType` value to point at, so the exception is created without one, even if `BasicJsonType` was built with
+`JSON_DIAGNOSTICS` enabled.
+
+## Complexity
+
+Linear in the size of the array or object: unlike [`front()`](front.md), which only ever looks at the first
+element, `back()` has to walk every element to find where they end, since elements are not a fixed size in the
+index.
+
+## Notes
+
+Unlike [`BasicJsonType::back()`](../basic_json/back.md), which has undefined behavior for an empty array or object,
+`back()` throws `invalid_iterator.214` in that case -- the same way it already does for `#!json null` and for a
+discarded view, where `BasicJsonType::back()` also throws.
+
+## Examples
+
+??? example
+
+    The example below reads only the final status of a build log with `back()`. Even though `back()` is linear in
+    the number of events (unlike [`front()`](front.md), which is constant), it still avoids building a
+    `BasicJsonType` value for the events that are not needed.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__back.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__back.output"
+    ```
+
+## See also
+
+- [front](front.md) - access the first element
+- [`BasicJsonType::back`](../basic_json/back.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,52 @@
+# <small>nlohmann::basic_json_view::</small>basic_json_view
+
+```cpp
+basic_json_view() noexcept = default;
+```
+
+Creates an invalid (discarded) view: [`type()`](type.md) is `#!cpp value_t::discarded`,
+[`is_discarded()`](is_discarded.md) is `#!cpp true`, and `#!cpp explicit operator bool()` is `#!cpp false`.
+
+This is the only constructor a caller can use directly. Every other view is obtained from a
+[`basic_json_document`](../basic_json_document/index.md), via [`root()`](../basic_json_document/root.md) or by
+navigating into a container with [`operator[]`](operator[].md), [`at`](at.md), [`front`](front.md), [`back`](back.md),
+[`find`](find.md), or iteration.
+
+## Exception safety
+
+No-throw guarantee: this constructor never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Notes
+
+`basic_json_view` is trivially copyable (it holds two pointers), so a default-constructed view can be used as a
+placeholder for "no value yet" and later be assigned a real view.
+
+## Examples
+
+??? example
+
+    The example below shows the default constructor and that a `basic_json_view` is a small, copyable handle.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__basic_json_view.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__basic_json_view.output"
+    ```
+
+## See also
+
+- [is_discarded](is_discarded.md) - return whether the view is invalid
+- [operator bool](operator_bool.md) - return whether the view refers to a value
+- [root](../basic_json_document/root.md) - the view of a document's root value
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,61 @@
+# <small>nlohmann::basic_json_view::</small>begin
+
+```cpp
+iterator begin() const noexcept;
+```
+
+Returns an iterator to the first element of an array, or the first member value of an object, in **document order**
+-- the order the values appear in the source text, not sorted by key. A primitive value iterates as a range of one
+element (itself); `#!json null` and a [discarded](is_discarded.md) view iterate as an empty range.
+
+## Return value
+
+Iterator to the first element.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Notes
+
+For an object, iteration visits **every** member, including all occurrences of a duplicate key -- unlike
+[`operator[]`](operator[].md), [`at`](at.md), [`find`](find.md), [`contains`](contains.md), and [`count`](count.md),
+which all resolve to the *first* member with a given key. See the
+[Notes on duplicate keys](operator[].md#notes) of `operator[]`.
+
+Because objects are iterated in document order rather than sorted by key, the order seen here can differ from what
+iterating the [`materialize()`](materialize.md)d `BasicJsonType` value would produce: a `#!cpp basic_json` object
+(`std::map`-backed by default) sorts its keys, while a view does not.
+
+## Examples
+
+??? example
+
+    The example below iterates a log record's members with `begin()`/[`end()`](end.md) and prints them in the order
+    they were written. Materializing the record into a `BasicJsonType` object and iterating that would instead print
+    the members sorted by key.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__begin.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__begin.output"
+    ```
+
+## See also
+
+- [end](end.md) - returns an iterator to one past the last element
+- [cbegin](cbegin.md) - returns a const iterator to the first element
+- [items](items.md) - access iterator member functions in range-based for
+- [`BasicJsonType::begin`](../basic_json/begin.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,49 @@
+# <small>nlohmann::basic_json_view::</small>cbegin
+
+```cpp
+iterator cbegin() const noexcept;
+```
+
+Returns an iterator to the first element, in [document order](begin.md). Equivalent to [`begin()`](begin.md): a view
+is always read-only, so `#!cpp const_iterator` and `#!cpp iterator` are the same type, and `cbegin()` exists only so
+that generic code that expects a `cbegin()`/`cend()` pair works with a view too.
+
+## Return value
+
+Iterator to the first element; identical to what [`begin()`](begin.md) returns.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Examples
+
+??? example
+
+    The example below sums many measurements with `std::accumulate`, using `cbegin()`/[`cend()`](cend.md) as the
+    range -- the same way it would for any standard container -- without ever materializing the whole array into a
+    `BasicJsonType` value.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__cbegin.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__cbegin.output"
+    ```
+
+## See also
+
+- [begin](begin.md) - returns an iterator to the first element
+- [cend](cend.md) - returns a const iterator to one past the last element
+- [`BasicJsonType::cbegin`](../basic_json/cbegin.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,49 @@
+# <small>nlohmann::basic_json_view::</small>cend
+
+```cpp
+iterator cend() const noexcept;
+```
+
+Returns an iterator to one past the last element, in [document order](begin.md). Equivalent to [`end()`](end.md): a
+view is always read-only, so `#!cpp const_iterator` and `#!cpp iterator` are the same type, and `cend()` exists only
+so that generic code that expects a `cbegin()`/`cend()` pair works with a view too.
+
+## Return value
+
+Iterator one past the last element; identical to what [`end()`](end.md) returns.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Examples
+
+??? example
+
+    The example below checks that every record of a batch is an object with `std::all_of`, using
+    [`cbegin()`](cbegin.md)/`cend()` as the range -- the same way it would for any standard container -- before
+    materializing any record of the batch.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__cend.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__cend.output"
+    ```
+
+## See also
+
+- [end](end.md) - returns an iterator to one past the last element
+- [cbegin](cbegin.md) - returns a const iterator to the first element
+- [`BasicJsonType::cend`](../basic_json/cend.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,103 @@
+# <small>nlohmann::basic_json_view::</small>contains
+
+```cpp
+// (1)
+bool contains(string_view_t key) const;
+bool contains(const char* key) const;
+bool contains(const string_t& key) const;
+
+// (2)
+bool contains(const json_pointer& ptr) const;
+```
+
+1. Checks whether the value is an object with a member with key `key`.
+2. Checks whether a JSON pointer `ptr` can be resolved, starting at this value.
+
+## Parameters
+
+`key` (in)
+:   key value to check its existence
+
+`ptr` (in)
+:   JSON pointer to check its existence
+
+## Return value
+
+1. `#!cpp true` if the value is an object and has a member with key `key`, `#!cpp false` otherwise
+2. `#!cpp true` if `ptr` can be resolved to a value starting at this view, `#!cpp false` otherwise
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+1. Linear in the number of members: as for [`ordered_json`](../ordered_json.md), members are compared one after
+   another, in document order, stopping at the first match. Each comparison first checks the key's length -- already
+   known from the index, without reading the key bytes -- before comparing its content.
+   Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time
+   on average.
+2. Linear in the number of reference tokens of `ptr` and, for each token, in the number of members of the object at
+   that level or the index into the array -- as for [`operator[]`](operator[].md#complexity) and
+   [`at`](at.md#complexity) with a JSON pointer.
+
+## Notes
+
+Overload 1 always returns `#!cpp false` when the value is not an object -- including a [discarded](is_discarded.md)
+view.
+
+!!! info "Postconditions"
+
+    If `#!cpp v.contains(key)` returns `#!cpp true`, then `#!cpp v[key]` is not [discarded](is_discarded.md). If
+    `#!cpp v.contains(ptr)` returns `#!cpp true`, then `#!cpp v[ptr]` is not discarded and `#!cpp v.at(ptr)` does not
+    throw.
+
+!!! info "Overload 2 never throws"
+
+    Unlike [`BasicJsonType::contains(const json_pointer&)`](../basic_json/contains.md), which can throw for certain
+    malformed pointers (for instance an empty array-index reference token), overload 2 never throws: a missing key,
+    an out-of-range or malformed array index, a `#!cpp "-"` index, or a reference token used on a primitive all
+    simply make it return `#!cpp false`.
+
+## Examples
+
+??? example "Example: (1) check with key"
+
+    The example below counts how many of a batch of records carry an optional `retry_of` field, using `contains()`
+    to check without ever materializing a single record of the batch.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__contains.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__contains.output"
+    ```
+
+??? example "Example: (2) check with JSON pointer"
+
+    The example below checks an optional, nested field with a JSON pointer, and shows two pointers that
+    `#!cpp contains()` resolves to `#!cpp false` without throwing.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__contains_json_pointer.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__contains_json_pointer.output"
+    ```
+
+## See also
+
+- [find](find.md) - find a value in an object
+- [count](count.md) - returns the number of occurrences of a key
+- [at](at.md), [operator[]](operator[].md) - resolve a JSON pointer and throw, or return a discarded view
+- [`BasicJsonType::contains`](../basic_json/contains.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,68 @@
+# <small>nlohmann::basic_json_view::</small>count
+
+```cpp
+size_type count(string_view_t key) const;
+size_type count(const char* key) const;
+size_type count(const string_t& key) const;
+```
+
+Returns `#!cpp 1` if the value is an object with a member with key `key`, `#!cpp 0` otherwise.
+
+## Parameters
+
+`key` (in)
+:   key value of the element to count
+
+## Return value
+
+`#!cpp 1` if the value is an object and has a member with key `key`, `#!cpp 0` otherwise.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Linear in the number of members: as for [`ordered_json`](../ordered_json.md), members are compared one after
+another, in document order, stopping at the first match. Each comparison first checks the key's length -- already
+known from the index, without reading the key bytes -- before comparing its content.
+Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time on
+average.
+
+## Notes
+
+This method always returns `#!cpp 0` when the value is not an object -- including a [discarded](is_discarded.md)
+view.
+
+Unlike [`BasicJsonType::count()`](../basic_json/count.md), whose return value can in principle exceed `#!cpp 1` for
+an `ObjectType` that allows multiple entries per key, `count()` here never does: it is exactly
+[`contains()`](contains.md) as `#!cpp 0`/`#!cpp 1`. This holds even if the source text has a duplicate key -- see the
+[Notes on duplicate keys](operator[].md#notes) of `operator[]` -- because a `#!cpp count() > 1` result would require
+counting every member with a matching key, not just finding the first one.
+
+## Examples
+
+??? example
+
+    The example below validates that every transaction of a batch carries a mandatory `amount` field, using
+    `count()` before deciding whether to materialize a transaction at all.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__count.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__count.output"
+    ```
+
+## See also
+
+- [find](find.md) - find a value in an object
+- [contains](contains.md) - checks whether a key exists
+- [`BasicJsonType::count`](../basic_json/count.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,102 @@
+# <small>nlohmann::basic_json_view::</small>dump
+
+```cpp
+string_t dump(const int indent = -1,
+              const char indent_char = ' ',
+              const bool ensure_ascii = false,
+              const number_format numbers = number_format::shortest) const;
+```
+
+Serializes this value (and its subtree) directly from the flat index, without ever building a `BasicJsonType` value
+first. With the default `#!cpp numbers == number_format::shortest`, the result is the same string
+[`BasicJsonType::dump`](../basic_json/dump.md) would produce for the value
+[`BasicJsonType::parse()`](../basic_json/parse.md) builds from the same source text, called with the same `indent`,
+`indent_char`, and `ensure_ascii` -- except that members of an object appear in document order rather than sorted by
+key, and *every* occurrence of a repeated key is written rather than only the last one (see
+[Notes on duplicate keys](operator[].md#notes)). For a `json_view` (whose `BasicJsonType` is not ordered), this means
+`dump()` can print an object's members in a different order than [`materialize()`](materialize.md)`.dump()` of the
+same subtree.
+
+## Parameters
+
+`indent` (in)
+:   If `indent` is nonnegative, array elements and object members are pretty-printed with that indent level. An
+    indent level of `0` only inserts newlines. `-1` (the default) selects the most compact representation.
+
+`indent_char` (in)
+:   The character used for indentation if `indent` is greater than `0`. The default is ` ` (space).
+
+`ensure_ascii` (in)
+:   If `ensure_ascii` is `#!cpp true`, all non-ASCII characters in the output are escaped with `\uXXXX` sequences, and
+    the result consists of ASCII characters only.
+
+`numbers` (in)
+:   how to write numbers, see [`number_format`](number_format.md): `shortest` (the default) writes them the way
+    [`BasicJsonType::dump`](../basic_json/dump.md) would; `source` copies every number exactly as it appears in the
+    source text.
+
+## Return value
+
+string containing the serialization of this value, or `#!cpp "<discarded>"` if the view is
+[discarded](is_discarded.md).
+
+## Exception safety
+
+Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
+
+## Exceptions
+
+May throw `#!cpp std::bad_alloc` if allocating the output string fails. Unlike
+[`BasicJsonType::dump`](../basic_json/dump.md), there is no `error_handler` parameter and no
+[`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316): the view only ever holds text the parser
+already validated as UTF-8, so there is nothing to replace or ignore.
+
+## Complexity
+
+Linear in the size of the output text.
+
+## Notes
+
+The walk over the subtree is iterative, so the nesting depth it can write is limited by available memory only, not by
+the call stack -- as for [`materialize()`](materialize.md).
+
+Strings are escaped by the same rules as [`BasicJsonType::dump`](../basic_json/dump.md). With
+`#!cpp numbers == number_format::shortest`, floats are written with the library's shortest round-trip conversion,
+exactly as [`BasicJsonType::dump`](../basic_json/dump.md) would (e.g. `#!cpp 1.5`, `#!cpp 100.0`, `#!cpp 1e+100`), and
+integers are copied from the source text -- already canonical in JSON, so this matches their shortest form too --
+except that `#!cpp -0` is written as `#!cpp 0`, the way [`BasicJsonType::parse()`](../basic_json/parse.md) reads it.
+`#!cpp number_format::source` copies every number exactly as written in the source text instead, with no exception
+for `#!cpp -0` -- `#!cpp 1.50`, `#!cpp 1E2`, `#!cpp -0.0`, `#!cpp -0`, or all digits of an integer literal with more
+digits than any number type holds (such a literal is itself classified as a float, see
+[What is different](../../features/json_view.md#what-is-different)) -- something `BasicJsonType` cannot do, since
+parsing already reduces every number to its parsed value.
+
+## Examples
+
+??? example
+
+    The example below forwards a single record out of a larger batch, and re-serializes a configuration file, both
+    without ever building a `BasicJsonType` value for the surrounding array or for the parts of it that were not
+    needed. It also shows that [`materialize()`](materialize.md)`.dump()` of the configuration sorts its keys, where
+    `dump()` on the view keeps the order they appear in the source text.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__dump.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__dump.output"
+    ```
+
+## See also
+
+- [`number_format`](number_format.md) - how `dump()` writes numbers
+- [operator<<](operator_ltlt.md) - serialize this value to a stream
+- [materialize](materialize.md) - build a `BasicJsonType` value, e.g. to use `BasicJsonType::dump`'s `error_handler`
+- [`BasicJsonType::dump`](../basic_json/dump.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,61 @@
+# <small>nlohmann::basic_json_view::</small>empty
+
+```cpp
+bool empty() const noexcept;
+```
+
+Checks whether [`size()`](size.md) is `0`, as [`BasicJsonType::empty()`](../basic_json/empty.md) would for the same
+value.
+
+## Return value
+
+The return value depends on the type and is defined as follows:
+
+| Value type          | return value    |
+|----------------------|-----------------|
+| null                  | `#!cpp true`     |
+| discarded             | `#!cpp true`     |
+| boolean               | `#!cpp false`    |
+| string                | `#!cpp false`    |
+| number                | `#!cpp false`    |
+| object                | `#!cpp object_t::empty()` |
+| array                 | `#!cpp array_t::empty()`  |
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Notes
+
+As for [`BasicJsonType::empty()`](../basic_json/empty.md), this does not return whether a string value is empty -- it
+is `#!cpp false` for any string, regardless of its length.
+
+## Examples
+
+??? example
+
+    The example below uses [`size()`](size.md) and `empty()` to decide whether a parsed message is worth acting on,
+    without materializing it into a `BasicJsonType` value.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__size_empty.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__size_empty.output"
+    ```
+
+## See also
+
+- [size](size.md) - return the number of elements
+- [`BasicJsonType::empty`](../basic_json/empty.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,54 @@
+# <small>nlohmann::basic_json_view::</small>end
+
+```cpp
+iterator end() const noexcept;
+```
+
+Returns an iterator to one past the last element of an array, one past the last member value of an object, in
+**document order** -- see [`begin()`](begin.md). A primitive value iterates as a range of one element (itself);
+`#!json null` and a [discarded](is_discarded.md) view iterate as an empty range, so `#!cpp begin() == end()` for
+them.
+
+## Return value
+
+Iterator one past the last element.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Notes
+
+`#!cpp iterator` is a forward iterator: unlike `BasicJsonType::iterator`, it cannot be decremented, so there is no
+way to reach the last element by stepping back from `end()`. Use [`back()`](back.md) instead.
+
+## Examples
+
+??? example
+
+    The example below scans a (possibly large) array of readings for the first one over a threshold, stopping the
+    loop at `end()` as soon as one is found. Only the matching reading, if any, is ever materialized.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__end.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__end.output"
+    ```
+
+## See also
+
+- [begin](begin.md) - returns an iterator to the first element
+- [cend](cend.md) - returns a const iterator to one past the last element
+- [`BasicJsonType::end`](../basic_json/end.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,65 @@
+# <small>nlohmann::basic_json_view::</small>find
+
+```cpp
+iterator find(string_view_t key) const;
+iterator find(const char* key) const;
+iterator find(const string_t& key) const;
+```
+
+Finds a member with key `key` -- the first one, should the key occur more than once (see
+[Notes on duplicate keys](operator[].md#notes)). If the value is not an object, or no member has this key,
+[`end()`](end.md) is returned.
+
+## Parameters
+
+`key` (in)
+:   key value of the element to search for
+
+## Return value
+
+An iterator to the member with key `key`, or [`end()`](end.md) if there is none or the value is not an object.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Linear in the number of members: as for [`ordered_json`](../ordered_json.md), members are compared one after
+another, in document order, stopping at the first match. Each comparison first checks the key's length -- already
+known from the index, without reading the key bytes -- before comparing its content.
+Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time on
+average.
+
+## Notes
+
+Unlike [`BasicJsonType::find`](../basic_json/find.md), which always returns `#!cpp end()` for a non-object type, this
+also does so for a [discarded](is_discarded.md) view -- there is no separate "invalid" iterator to return.
+
+## Examples
+
+??? example
+
+    The example below scans a batch of events for those that carry an optional `user_id` field, using `find()`
+    instead of [`operator[]`](operator[].md) (which would throw for the events that are not objects at all) or
+    [`contains()`](contains.md) followed by a second lookup. Events without a match are never materialized.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__find.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__find.output"
+    ```
+
+## See also
+
+- [count](count.md) - returns the number of occurrences of a key
+- [contains](contains.md) - checks whether a key exists
+- [`BasicJsonType::find`](../basic_json/find.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,61 @@
+# <small>nlohmann::basic_json_view::</small>front
+
+```cpp
+basic_json_view front() const;
+```
+
+Returns the first element of an array, the first member value of an object, or the value itself if it is primitive
+(as for [`BasicJsonType::front()`](../basic_json/front.md), a primitive value is a range of one element).
+
+## Return value
+
+The first element or member value. For a primitive value (number, string, boolean), the value itself.
+
+## Exception safety
+
+Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
+
+## Exceptions
+
+Throws [`invalid_iterator.214`](../../home/exceptions.md#jsonexceptioninvalid_iterator214) if the view is
+[null](is_null.md) or [discarded](is_discarded.md), or if it is an empty array or object.
+
+This exception does not carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) path: the view has no
+`BasicJsonType` value to point at, so the exception is created without one, even if `BasicJsonType` was built with
+`JSON_DIAGNOSTICS` enabled.
+
+## Complexity
+
+Constant.
+
+## Notes
+
+Unlike [`BasicJsonType::front()`](../basic_json/front.md), which has undefined behavior for an empty array or
+object, `front()` throws `invalid_iterator.214` in that case -- the same way it already does for `#!json null` and
+for a discarded view, where `BasicJsonType::front()` also throws.
+
+## Examples
+
+??? example
+
+    The example below reads only the earliest entry of a build log with `front()`, without materializing the rest
+    of the (possibly long) log.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__front.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__front.output"
+    ```
+
+## See also
+
+- [back](back.md) - access the last element
+- [`BasicJsonType::front`](../basic_json/front.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,130 @@
+# <small>nlohmann::basic_json_view::</small>get
+
+```cpp
+template<typename T>
+T get() const;
+```
+
+Converts the value to `T`.
+
+For the types below, the conversion works directly on the flat index -- no `BasicJsonType` value is built for it:
+
+- `#!cpp bool`
+- arithmetic types other than `#!cpp bool` (from a number; from a boolean, as `#!cpp 0`/`#!cpp 1`, exactly as
+  [`BasicJsonType::get<T>()`](../basic_json/get.md) converts a boolean)
+- `#!cpp std::nullptr_t`
+- `#!cpp std::basic_string<char, Traits, Alloc>` (including `string_t`) -- a copy of the string
+- [`string_view_t`](index.md#member-types) -- **no copy**: the returned view points into the document's
+  [`source()`](../basic_json_document/source.md) text, or, for a string that contains escape sequences, into the
+  document's own buffer of decoded strings (see [`get_string()`](get_string.md))
+- `BasicJsonType` -- equivalent to [`materialize()`](materialize.md)
+- `basic_json_view` -- returns `#!cpp *this`
+- `#!cpp std::vector<U, A>` -- element by element, each converted with `#!cpp get<U>()`; `#!cpp
+  std::vector<basic_json_view>` keeps a view of every element instead of a value
+- `#!cpp std::map<K, V, C, A>` and `#!cpp std::unordered_map<K, V, H, E, A>`, if `K` is constructible from a `#!cpp
+  (const char*, std::size_t)` pair -- member by member, each value converted with `#!cpp get<V>()`; with a repeated
+  key, the *last* value is kept, as [`BasicJsonType::parse()`](../basic_json/parse.md) (and
+  [`materialize()`](materialize.md)) does; `#!cpp std::map<std::string, basic_json_view>` keeps views of the members
+  instead of values
+
+Every other `T` -- `#!cpp std::list`, `#!cpp std::pair`, `#!cpp std::array`, enumerations, user types with a
+`from_json()`, ... -- is converted by `#!cpp materialize().get<T>()`: the subtree is built into a real `BasicJsonType`
+value first (as [`BasicJsonType::parse()`](../basic_json/parse.md) would), and converted from there exactly as
+[`BasicJsonType::get<T>()`](../basic_json/get.md) would convert it.
+
+## Template parameters
+
+`T`
+:   the type to convert the value to
+
+## Return value
+
+the value, converted to `T`
+
+## Exception safety
+
+Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
+
+## Exceptions
+
+- For the directly-converted types listed above (other than `BasicJsonType` and `basic_json_view`, which never
+  throw): throws [`type_error.302`](../../home/exceptions.md#jsonexceptiontype_error302) if the value's type does not
+  match `T` -- the same exception, with the same message, that [`BasicJsonType::get<T>()`](../basic_json/get.md)
+  throws for the same JSON type and `T`.
+- For `#!cpp std::vector<U, A>`: throws `type_error.302` if the value is not an array; otherwise, whatever converting
+  an element to `U` throws.
+- For `#!cpp std::map`/`#!cpp std::unordered_map`: throws `type_error.302` if the value is not an object; otherwise,
+  whatever converting a member to the mapped type throws.
+- For every other `T`: whatever [`materialize().get<T>()`](../basic_json/get.md) throws -- typically `type_error.302`,
+  or whatever a user-provided `from_json()` throws.
+
+None of the exceptions thrown directly by this function (the first three bullets above) carry a
+[`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) path: the view has no `BasicJsonType` value to point at. An
+exception thrown while converting through `materialize()` (the last bullet) is different: it is thrown by a real
+`BasicJsonType` value, so it **does** carry a `JSON_DIAGNOSTICS` path if `BasicJsonType` was built with it enabled.
+
+## Complexity
+
+- `#!cpp bool`, arithmetic types, `#!cpp std::nullptr_t`, [`string_view_t`](index.md#member-types), `basic_json_view`:
+  constant.
+- `#!cpp std::basic_string<char, Traits, Alloc>`: constant, plus one allocation and a copy of the string's bytes.
+- `BasicJsonType`: linear in the size of the subtree, see [`materialize()`](materialize.md).
+- `#!cpp std::vector<U, A>`: linear in the number of elements, times the complexity of converting one element to `U`.
+- `#!cpp std::map`/`#!cpp std::unordered_map`: linear in the number of members for walking them, plus the container's
+  own insertion cost per member (logarithmic for `#!cpp std::map`, amortized constant for `#!cpp
+  std::unordered_map`), times the complexity of converting one member to the mapped type.
+- every other `T`: linear in the size of the subtree (building the `BasicJsonType` value), plus the complexity of
+  [`BasicJsonType::get<T>()`](../basic_json/get.md) on it.
+
+## Notes
+
+!!! info "Floating-point values"
+
+    A floating-point `T` is converted from the same digits the lexer would see during `#!cpp BasicJsonType::parse()`,
+    using the same conversion, so the result is bit-for-bit identical to `#!cpp BasicJsonType::parse(text).get<T>()`
+    for the same source text.
+
+!!! info "Duplicate keys"
+
+    `#!cpp std::map`/`#!cpp std::unordered_map` conversions keep the *last* value of a repeated key, like
+    [`materialize()`](materialize.md) and [`BasicJsonType::parse()`](../basic_json/parse.md) do. This is the opposite
+    of [`operator[]`](operator[].md)/[`at`](at.md)/[`find`](find.md)/[`contains`](contains.md), which resolve to the
+    *first* occurrence (see the [Notes on duplicate keys](operator[].md#notes)).
+
+!!! info "No pointers, references, or implicit conversion"
+
+    Unlike `BasicJsonType`, `basic_json_view` has no stored value anywhere to hand out a pointer or a reference to, so
+    it provides neither `#!cpp get_ptr()`, `#!cpp get_ref()`, nor `#!cpp operator ValueType()`.
+    [`get_string()`](get_string.md) (equivalently, `#!cpp get<string_view_t>()`) is the zero-copy alternative for
+    strings.
+
+## Examples
+
+??? example
+
+    The example below reads typed fields straight into C++ variables, collects a view of every array element with
+    `#!cpp get<std::vector<basic_json_view>>()` instead of a value, and converts a nested object into a user type
+    through its `from_json()` -- which runs on a `BasicJsonType` value `materialize()` builds for just that one
+    member.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__get.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__get.output"
+    ```
+
+## See also
+
+- [get_to](get_to.md) - convert and write into a passed value
+- [get_string](get_string.md) - the string, without a copy
+- [number_token](number_token.md) - a number's token text, without a copy
+- [materialize](materialize.md) - build the `BasicJsonType` value of this subtree
+- [`BasicJsonType::get`](../basic_json/get.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,71 @@
+# <small>nlohmann::basic_json_view::</small>get_string
+
+```cpp
+string_view_t get_string() const;
+```
+
+Returns the string value as a [`string_view_t`](index.md#member-types), without copying it.
+
+## Return value
+
+The string, as a [`string_view_t`](index.md#member-types) that points either into the document's
+[`source()`](../basic_json_document/source.md) text (a string with no escape sequences), or into the document's own
+buffer of decoded strings (a string that contains escape sequences, such as `#!json "\n"` or `#!json "\u00e9"`, which
+had to be decoded once when the document was parsed).
+
+## Exception safety
+
+Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
+
+## Exceptions
+
+Throws [`type_error.302`](../../home/exceptions.md#jsonexceptiontype_error302) if the value is not a string; example:
+`"type must be string, but is array"`.
+
+This exception does not carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) path: the view has no
+`BasicJsonType` value to point at, so the exception is created without one, even if `BasicJsonType` was built with
+`JSON_DIAGNOSTICS` enabled.
+
+## Complexity
+
+Constant.
+
+## Notes
+
+`basic_json_view` has no `BasicJsonType` value stored anywhere, so unlike `BasicJsonType`, it has no `get_ref()` to
+hand out a reference to a stored `string_t`. `get_string()` (equivalently, [`get<string_view_t>()`](get.md)) is the
+zero-copy alternative: [`BasicJsonType::get_ref<const string_t&>()`](../basic_json/get_ref.md) is its closest
+counterpart, except that it returns a view instead of a reference to a value that must already exist.
+
+The returned [`string_view_t`](index.md#member-types) is valid exactly as long as the view that produced it -- see the
+[validity rules](index.md) of `basic_json_view` -- and, for a string with no escapes, for as long as the document's
+source text.
+
+## Examples
+
+??? example
+
+    The example below pulls one field out of a JSON text that stands in for a large API response, and shows that no
+    `#!cpp std::string` was allocated for it: the returned view still points inside the original buffer. A field that
+    contains an escape sequence cannot point into the original text -- it was decoded once into the document's own
+    buffer instead -- but still avoids a per-field allocation.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__get_string.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__get_string.output"
+    ```
+
+## See also
+
+- [get](get.md) - convert the value to a given type (`#!cpp get<string_view_t>()` is equivalent to this function)
+- [number_token](number_token.md) - a number's token text, without a copy
+- [`BasicJsonType::get_ref`](../basic_json/get_ref.md) - the closest counterpart of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,65 @@
+# <small>nlohmann::basic_json_view::</small>get_to
+
+```cpp
+template<typename T>
+T& get_to(T& v) const;
+```
+
+Converts the value to `T` and assigns it to `v`. Equivalent to
+
+```cpp
+v = get<T>();
+return v;
+```
+
+## Template parameters
+
+`T`
+:   the type to convert the value to
+
+## Parameters
+
+`v` (out)
+:   the variable to store the converted value in
+
+## Return value
+
+`v`, allowing calls to chain
+
+## Exception safety
+
+Strong exception safety: if an exception is thrown, `v` is not modified.
+
+## Exceptions
+
+Whatever [`get<T>()`](get.md) throws for the same value and `T`.
+
+## Complexity
+
+Whatever [`get<T>()`](get.md) has for the same `T`.
+
+## Examples
+
+??? example
+
+    The example below reads several fields of a service configuration directly into existing variables, then uses
+    the returned reference to fold the `#!cpp host`/`#!cpp port` pair into a single string in the same expression.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__get_to.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__get_to.output"
+    ```
+
+## See also
+
+- [get](get.md) - convert the value to a given type
+- [`BasicJsonType::get_to`](../basic_json/get_to.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,141 @@
+# <small>nlohmann::</small>basic_json_view
+
+<small>Defined in header `<nlohmann/json_view.hpp>`</small>
+
+```cpp
+template<typename BasicJsonType, bool Editable = false>
+class basic_json_view;
+```
+
+A read-only handle to one value of a [`basic_json_document`](../basic_json_document/index.md): two pointers (a pointer
+to the document and a pointer into its index), trivially copyable. A view is valid as long as
+
+- the document is alive,
+- the document has not been re-parsed with [`read()`](../basic_json_document/read.md) (or
+  [`parse()`](../basic_json_document/parse.md) into it) or shrunk with
+  [`shrink_to_fit()`](../basic_json_document/shrink_to_fit.md) since the view was taken, and
+- if the document borrows its source text, that text is still alive.
+
+Moving the document itself does not invalidate its views: the index is heap-allocated independently of the
+`basic_json_document` object.
+
+`basic_json_view` provides the read-only part of the `BasicJsonType` interface: the type-inspection functions, element
+access, lookup, iteration, conversion, and comparison -- [`get<T>()`](get.md), [`get_string()`](get_string.md),
+[`number_token()`](number_token.md), and [`materialize()`](materialize.md) to build the `BasicJsonType` value of a
+subtree on demand. [`operator[]`](operator%5B%5D.md), [`at`](at.md), [`contains`](contains.md), and
+[`value`](value.md) also accept a [`json_pointer`](../json_pointer/index.md). [`operator==`](operator_eq.md) and
+[`operator!=`](operator_ne.md) compare two views, or a view and a `BasicJsonType` value, without ever building a
+`BasicJsonType` value for a view; no ordering comparison (`#!cpp operator<`) is provided.
+
+`basic_json_view` itself is always read-only -- it never has a `set` or `push_back` of its own. A view of an
+**editable** document (`#!cpp Editable == true`) sees every edit made through
+[`basic_json_document::set`](../basic_json_document/set.md) and
+[`basic_json_document::push_back`](../basic_json_document/push_back.md): once a value is changed, every view that
+still refers to it -- including ones taken before the change -- reads the new value. See
+[Edits](../basic_json_document/index.md#edits).
+
+## Template parameters
+
+`BasicJsonType`
+:   a specialization of [`basic_json`](../basic_json/index.md), matching the
+    [`basic_json_document`](../basic_json_document/index.md) the view was taken from.
+
+`Editable`
+:   whether the view is of an editable document, matching the [`basic_json_document`](../basic_json_document/index.md)
+    it was taken from (optional, `#!cpp false` by default). See [Edits](../basic_json_document/index.md#edits).
+
+## Specializations
+
+- [**json_view**](../json_view.md) - views of a [`json_document`](../json_document.md)
+- [**ordered_json_view**](../ordered_json_view.md) - views of an [`ordered_json_document`](../ordered_json_document.md)
+- [**json_editable_view**](../json_editable_view.md) - views of a [`json_editable_document`](../json_editable_document.md)
+- [**ordered_json_editable_view**](../ordered_json_editable_view.md) - views of an
+  [`ordered_json_editable_document`](../ordered_json_editable_document.md)
+
+## Member types
+
+- **value_t** - the JSON type enumeration, see [`basic_json::value_t`](../basic_json/value_t.md)
+- **string_t**, **number_integer_t**, **number_unsigned_t**, **number_float_t**, **json_pointer** - the corresponding
+  member types of `BasicJsonType`
+- **size_type** - `#!cpp std::size_t`
+- **string_view_t** - `#!cpp std::string_view` on C++17 and newer, a minimal internal substitute otherwise
+- **iterator**, **const_iterator** - a forward iterator over the elements of an array or the member values of an
+  object, in document order; both names refer to the same type, since a view is always read-only
+- **item** - a (key, value) pair produced by [`items()`](items.md)
+- [**number_format**](number_format.md) - how [`dump()`](dump.md) writes numbers
+
+## Member functions
+
+- [(constructor)](basic_json_view.md)
+
+### Object inspection
+
+- [**type**](type.md) - return the type of the value
+- [**type_name**](type_name.md) - return the type as string
+- [**is_null**](is_null.md) - return whether the value is null
+- [**is_boolean**](is_boolean.md) - return whether the value is a boolean
+- [**is_number**](is_number.md) - return whether the value is a number
+- [**is_number_integer**](is_number_integer.md) - return whether the value is an integer number
+- [**is_number_unsigned**](is_number_unsigned.md) - return whether the value is an unsigned integer number
+- [**is_number_float**](is_number_float.md) - return whether the value is a floating-point number
+- [**is_string**](is_string.md) - return whether the value is a string
+- [**is_array**](is_array.md) - return whether the value is an array
+- [**is_object**](is_object.md) - return whether the value is an object
+- [**is_binary**](is_binary.md) - return whether the value is a binary array (always `#!cpp false`)
+- [**is_primitive**](is_primitive.md) - return whether the type is primitive
+- [**is_structured**](is_structured.md) - return whether the type is structured
+- [**is_discarded**](is_discarded.md) - return whether the view is invalid
+- [**operator bool**](operator_bool.md) - return whether the view refers to a value
+
+### Element access
+
+- [**at**](at.md) - access specified element with bounds checking
+- [**operator[]**](operator[].md) - access specified element
+- [**value**](value.md) - access specified element with default value
+- [**front**](front.md) - access the first element
+- [**back**](back.md) - access the last element
+
+### Lookup
+
+- [**find**](find.md) - find an element in an object
+- [**count**](count.md) - returns the number of occurrences of a key in an object
+- [**contains**](contains.md) - check the existence of an element in an object
+
+### Iterators
+
+- [**begin**](begin.md) - returns an iterator to the first element
+- [**cbegin**](cbegin.md) - returns a const iterator to the first element
+- [**end**](end.md) - returns an iterator to one past the last element
+- [**cend**](cend.md) - returns a const iterator to one past the last element
+- [**items**](items.md) - wrapper to access iterator member functions in range-based for
+
+### Capacity
+
+- [**size**](size.md) - return the number of elements
+- [**empty**](empty.md) - return whether the value has no elements
+
+### Conversion
+
+- [**get**](get.md) - get a value
+- [**get_to**](get_to.md) - get a value and write it to a destination
+- [**get_string**](get_string.md) - get a string value without a copy
+- [**number_token**](number_token.md) - get a number's token text without a copy
+- [**materialize**](materialize.md) - build the `BasicJsonType` value of this subtree
+
+### Comparison
+
+- [**operator==**](operator_eq.md) - comparison: equal
+- [**operator!=**](operator_ne.md) - comparison: not equal
+
+### Serialization
+
+- [**dump**](dump.md) - serialize to a JSON-formatted string
+- [**operator<<**](operator_ltlt.md) - serialize to stream
+
+### Source access
+
+- [**source_offset**](source_offset.md) - byte offset of this value in the document's source text
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,46 @@
+# <small>nlohmann::basic_json_view::</small>is_array
+
+```cpp
+bool is_array() const noexcept;
+```
+
+This function returns `#!cpp true` if and only if the value is an array.
+
+## Return value
+
+`#!cpp true` if the type is an array, `#!cpp false` otherwise.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Examples
+
+??? example
+
+    The example below classifies several parsed documents by the type of their root value, without materializing any
+    of them into a `BasicJsonType` value.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__type_predicates.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__type_predicates.output"
+    ```
+
+## See also
+
+- [is_structured](is_structured.md) - return whether the type is structured
+- [size](size.md), [empty](empty.md) - the number of elements, and whether there are none
+- [`BasicJsonType::is_array`](../basic_json/is_array.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,46 @@
+# <small>nlohmann::basic_json_view::</small>is_binary
+
+```cpp
+bool is_binary() const noexcept;
+```
+
+This function always returns `#!cpp false`: a JSON text has no binary values, so a view can never refer to one. The
+function exists for interface parity with [`BasicJsonType::is_binary`](../basic_json/is_binary.md).
+
+## Return value
+
+`#!cpp false`, always.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Examples
+
+??? example
+
+    The example below classifies several parsed documents by the type of their root value, without materializing any
+    of them into a `BasicJsonType` value.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__type_predicates.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__type_predicates.output"
+    ```
+
+## See also
+
+- [type](type.md) - return the type of the value
+- [`BasicJsonType::is_binary`](../basic_json/is_binary.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,45 @@
+# <small>nlohmann::basic_json_view::</small>is_boolean
+
+```cpp
+bool is_boolean() const noexcept;
+```
+
+This function returns `#!cpp true` if and only if the value is a boolean.
+
+## Return value
+
+`#!cpp true` if the type is a boolean, `#!cpp false` otherwise.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Examples
+
+??? example
+
+    The example below classifies several parsed documents by the type of their root value, without materializing any
+    of them into a `BasicJsonType` value.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__type_predicates.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__type_predicates.output"
+    ```
+
+## See also
+
+- [type](type.md) - return the type of the value
+- [`BasicJsonType::is_boolean`](../basic_json/is_boolean.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,55 @@
+# <small>nlohmann::basic_json_view::</small>is_discarded
+
+```cpp
+bool is_discarded() const noexcept;
+```
+
+Returns whether this view is invalid, i.e. does not refer to a value. This is the case for a default-constructed
+view (see [(constructor)](basic_json_view.md)), and for [`root()`](../basic_json_document/root.md) of a document
+that is itself [discarded](../basic_json_document/is_discarded.md) -- in particular, the root of a failed
+[`parse()`](../basic_json_document/parse.md) with `allow_exceptions` set to `#!cpp false`.
+
+## Return value
+
+`#!cpp true` if the view is discarded, `#!cpp false` otherwise.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Notes
+
+`#!cpp v.is_discarded()` and `#!cpp !static_cast<bool>(v)` are equivalent; use whichever reads better at the call
+site.
+
+## Examples
+
+??? example
+
+    The example below classifies several parsed documents by the type of their root value, without materializing any
+    of them into a `BasicJsonType` value.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__type_predicates.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__type_predicates.output"
+    ```
+
+## See also
+
+- [operator bool](operator_bool.md) - return whether the view refers to a value
+- [(constructor)](basic_json_view.md) - the default constructor creates a discarded view
+- [is_discarded (basic_json_document)](../basic_json_document/is_discarded.md) - return whether the last parse failed
+- [`BasicJsonType::is_discarded`](../basic_json/is_discarded.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,45 @@
+# <small>nlohmann::basic_json_view::</small>is_null
+
+```cpp
+bool is_null() const noexcept;
+```
+
+This function returns `#!cpp true` if and only if the value is `#!json null`.
+
+## Return value
+
+`#!cpp true` if the type is `#!json null`, `#!cpp false` otherwise.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Examples
+
+??? example
+
+    The example below classifies several parsed documents by the type of their root value, without materializing any
+    of them into a `BasicJsonType` value.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__type_predicates.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__type_predicates.output"
+    ```
+
+## See also
+
+- [type](type.md) - return the type of the value
+- [`BasicJsonType::is_null`](../basic_json/is_null.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,47 @@
+# <small>nlohmann::basic_json_view::</small>is_number
+
+```cpp
+bool is_number() const noexcept;
+```
+
+This function returns `#!cpp true` if and only if the value is a number, i.e. an integer, unsigned integer, or floating-point value. It is defined as `#!cpp is_number_integer() || is_number_float()`.
+
+## Return value
+
+`#!cpp true` if the type is a number, `#!cpp false` otherwise.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Examples
+
+??? example
+
+    The example below classifies several parsed documents by the type of their root value, without materializing any
+    of them into a `BasicJsonType` value.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__type_predicates.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__type_predicates.output"
+    ```
+
+## See also
+
+- [is_number_integer](is_number_integer.md) - return whether the value is an integer or unsigned integer number
+- [is_number_unsigned](is_number_unsigned.md) - return whether the value is an unsigned integer number
+- [is_number_float](is_number_float.md) - return whether the value is a floating-point number
+- [`BasicJsonType::is_number`](../basic_json/is_number.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,51 @@
+# <small>nlohmann::basic_json_view::</small>is_number_float
+
+```cpp
+bool is_number_float() const noexcept;
+```
+
+This function returns `#!cpp true` if and only if the value is a floating-point number.
+
+## Return value
+
+`#!cpp true` if the type is `#!cpp value_t::number_float`, `#!cpp false` otherwise.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Notes
+
+As for [`BasicJsonType::parse`](../basic_json/parse.md), an integer literal that does not fit into the 64-bit
+integer type is classified as a floating-point number, so `is_number_float()` can be `#!cpp true` even for an
+integer-looking token in the source text.
+
+## Examples
+
+??? example
+
+    The example below classifies several parsed documents by the type of their root value, without materializing any
+    of them into a `BasicJsonType` value.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__type_predicates.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__type_predicates.output"
+    ```
+
+## See also
+
+- [is_number](is_number.md) - return whether the value is a number
+- [`BasicJsonType::is_number_float`](../basic_json/is_number_float.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,51 @@
+# <small>nlohmann::basic_json_view::</small>is_number_integer
+
+```cpp
+bool is_number_integer() const noexcept;
+```
+
+This function returns `#!cpp true` if and only if the value is an integer or unsigned integer number.
+
+## Return value
+
+`#!cpp true` if the type is `#!cpp value_t::number_integer` or `#!cpp value_t::number_unsigned`, `#!cpp false` otherwise.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Notes
+
+As for [`BasicJsonType::is_number_integer`](../basic_json/is_number_integer.md), this includes unsigned integer
+values; use [`is_number_unsigned`](is_number_unsigned.md) to test for those specifically.
+
+## Examples
+
+??? example
+
+    The example below classifies several parsed documents by the type of their root value, without materializing any
+    of them into a `BasicJsonType` value.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__type_predicates.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__type_predicates.output"
+    ```
+
+## See also
+
+- [is_number](is_number.md) - return whether the value is a number
+- [is_number_unsigned](is_number_unsigned.md) - return whether the value is an unsigned integer number
+- [`BasicJsonType::is_number_integer`](../basic_json/is_number_integer.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,45 @@
+# <small>nlohmann::basic_json_view::</small>is_number_unsigned
+
+```cpp
+bool is_number_unsigned() const noexcept;
+```
+
+This function returns `#!cpp true` if and only if the value is an unsigned integer number.
+
+## Return value
+
+`#!cpp true` if the type is `#!cpp value_t::number_unsigned`, `#!cpp false` otherwise.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Examples
+
+??? example
+
+    The example below classifies several parsed documents by the type of their root value, without materializing any
+    of them into a `BasicJsonType` value.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__type_predicates.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__type_predicates.output"
+    ```
+
+## See also
+
+- [is_number_integer](is_number_integer.md) - return whether the value is an integer or unsigned integer number
+- [`BasicJsonType::is_number_unsigned`](../basic_json/is_number_unsigned.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,46 @@
+# <small>nlohmann::basic_json_view::</small>is_object
+
+```cpp
+bool is_object() const noexcept;
+```
+
+This function returns `#!cpp true` if and only if the value is an object.
+
+## Return value
+
+`#!cpp true` if the type is an object, `#!cpp false` otherwise.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Examples
+
+??? example
+
+    The example below classifies several parsed documents by the type of their root value, without materializing any
+    of them into a `BasicJsonType` value.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__type_predicates.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__type_predicates.output"
+    ```
+
+## See also
+
+- [is_structured](is_structured.md) - return whether the type is structured
+- [size](size.md), [empty](empty.md) - the number of elements, and whether there are none
+- [`BasicJsonType::is_object`](../basic_json/is_object.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
--- a/Show More
+++ b/Show More