Merge branch 'json-view/10-view-document' into json-view/11-view-access

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Mark json_view.hpp's read() and strlen as Flawfinder false positives
2026-10-01 20:20:32 +00:00 · 2026-10-01 10:27:03 +02:00 · 2026-10-01 10:27:01 +02:00 · 2026-10-01 10:26:20 +02:00 · 2026-10-01 10:26:18 +02:00 · 2026-10-01 10:19:51 +02:00
462 changed files with 18547 additions and 13935 deletions
@@ -1,9 +1,15 @@
-# TODO: The first three checks are only removed to get the CI going. They have to be addressed at some point.
-# TODO: portability-avoid-pragma-once: should be fixed eventually
+# bugprone-use-after-move (hicpp-invalid-access-moved is its alias) still flags
+# the basic_json move constructor, which forwards the whole object to its base
+# class (#5724), and two forwards in the error-message construction of
+# at(KeyType&&) (json.hpp, both overloads: find(std::forward<KeyType>(key))
+# followed by string_t(std::forward<KeyType>(key)) in the throw), which #5689
+# rewrites. Re-enable both checks once those changes have landed.
+# portability-avoid-pragma-once: kept disabled on purpose. #pragma once is accepted
+# by every supported compiler, and tools/amalgamate/amalgamate.py strips it from
+# single_include, so there is nothing left to fix here.

 Checks: '*,

-         -portability-template-virtual-member-function,
         -bugprone-use-after-move,
         -hicpp-invalid-access-moved,

@@ -37,7 +43,6 @@ Checks: '*,
         -google-readability-function-size,
         -google-runtime-float,
         -google-runtime-int,
-         -google-runtime-references,
         -hicpp-avoid-goto,
         -hicpp-explicit-conversions,
         -hicpp-function-size,
@@ -71,6 +76,7 @@ Checks: '*,
         -readability-magic-numbers,
         -readability-redundant-access-specifiers,
         -readability-redundant-parentheses,
+         -readability-redundant-typename,
         -readability-simplify-boolean-expr,
         -readability-uppercase-literal-suffix,
         -readability-use-concise-preprocessor-directives'
@@ -81,5 +87,4 @@ CheckOptions:

 WarningsAsErrors: '*'

-#HeaderFilterRegex: '.*nlohmann.*'
 HeaderFilterRegex: '.*hpp$'
@@ -45,6 +45,23 @@ 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\\.cpp"
+    - "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_(document|view)\\.md"
+    - "docs/mkdocs/docs/examples/(basic_json_(document|view)__|(ordered_)?json_(document|view)).*"
+    - "tests/benchmarks/src/benchmarks_view\\.cpp"
+
+- label: "aspect: json_view"
+  title: "(?i)(json_view|json_document|zero-copy)"
+
 - label: "python"
  files:
    - "\\.py$"
@@ -2,16 +2,23 @@ name: "Check amalgamation"

 on:
  pull_request:
+  # also check develop itself: a PR can be merged before its own run of this
+  # workflow completes (e.g. while it is still queued), leaving single_include
+  # stale on develop without any failing check
+  push:
+    branches:
+      - develop

 concurrency:
  group: ${{ github.workflow }}-${{ github.ref || github.run_id }}
-  cancel-in-progress: true
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}

 permissions:
  contents: read

 jobs:
  save:
+    if: github.event_name == 'pull_request'
    runs-on: ubuntu-latest
    steps:
      - name: Harden Runner
@@ -43,11 +50,11 @@ jobs:
        with:
          egress-policy: audit

-      - name: Checkout pull request
+      - name: Checkout pull request or pushed commit
        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
        with:
          path: main
-          ref: ${{ github.event.pull_request.head.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
          persist-credentials: false

      - name: Checkout tools
@@ -111,12 +118,15 @@ 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
@@ -38,14 +38,14 @@ jobs:

    # Initializes the CodeQL tools for scanning.
    - name: Initialize CodeQL
-      uses: github/codeql-action/init@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
+      uses: github/codeql-action/init@1c5b675653bb5c22dbe9b12b556ec555138e09fd # v4.38.1
      with:
        languages: c-cpp

    # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
    # If this step fails, then you should remove it and run the build manually (see below)
    - name: Autobuild
-      uses: github/codeql-action/autobuild@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
+      uses: github/codeql-action/autobuild@1c5b675653bb5c22dbe9b12b556ec555138e09fd # v4.38.1

    - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
+      uses: github/codeql-action/analyze@1c5b675653bb5c22dbe9b12b556ec555138e09fd # v4.38.1
@@ -10,7 +10,8 @@ permissions:

 jobs:
  comment:
-    if: ${{ github.event.workflow_run.conclusion == 'failure' }}
+    # push runs on develop have no PR to comment on (and no "pr" artifact)
+    if: ${{ github.event.workflow_run.conclusion == 'failure' && github.event.workflow_run.event == 'pull_request' }}
    runs-on: ubuntu-latest
    permissions:
      contents: read
@@ -47,6 +47,6 @@ jobs:
          output: 'flawfinder_results.sarif'

      - name: Upload analysis results to GitHub Security tab
-        uses: github/codeql-action/upload-sarif@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
+        uses: github/codeql-action/upload-sarif@1c5b675653bb5c22dbe9b12b556ec555138e09fd # v4.38.1
        with:
          sarif_file: ${{github.workspace}}/flawfinder_results.sarif
@@ -80,6 +80,6 @@ jobs:

      # Upload the results to GitHub's code scanning dashboard.
      - name: "Upload to code-scanning"
-        uses: github/codeql-action/upload-sarif@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
+        uses: github/codeql-action/upload-sarif@1c5b675653bb5c22dbe9b12b556ec555138e09fd # v4.38.1
        with:
          sarif_file: results.sarif
@@ -65,7 +65,7 @@ jobs:

      # Upload SARIF file generated in previous step
      - name: Upload SARIF file
-        uses: github/codeql-action/upload-sarif@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
+        uses: github/codeql-action/upload-sarif@1c5b675653bb5c22dbe9b12b556ec555138e09fd # v4.38.1
        with:
          sarif_file: semgrep.sarif
        if: always()
@@ -85,7 +85,7 @@ jobs:

  ci_static_analysis_clang:
    runs-on: ubuntu-latest
-    container: silkeh/clang:dev
+    container: silkeh/clang:22
    strategy:
      matrix:
        target: [ci_test_clang, ci_clang_tidy, ci_test_clang_sanitizer, ci_clang_analyze, ci_single_binaries]
@@ -23,10 +23,6 @@ Files: tests/thirdparty/fifo_map/*
 Copyright: 2015-2017 Niels Lohmann
 License: MIT

-Files: tests/thirdparty/Fuzzer/*
-Copyright: 2003-2022 LLVM Project.
-License: Apache-2.0
-
 Files: tests/thirdparty/imapdl/*
 Copyright: 2017 Georg Sauthoff <mail@gms.tf>
 License: GPL-3.0-only
@@ -20,6 +20,7 @@ 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",
@@ -65,9 +66,23 @@ 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/document_data.hpp",
+        "include/nlohmann/detail/view/errors.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/scan.hpp",
+        "include/nlohmann/detail/view/string_ref.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",
@@ -80,6 +95,7 @@ cc_library(
    name = "singleheader-json",
    hdrs = [
        "single_include/nlohmann/json.hpp",
+        "single_include/nlohmann/json_view.hpp",
    ],
    includes = ["single_include"],
    visibility = ["//visibility:public"],
@@ -23,6 +23,7 @@ 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

 # the header with the argument-counting macros generated by tools/macro_builder
 MACRO_SCOPE_HPP=include/nlohmann/detail/macro_scope.hpp
@@ -34,7 +35,7 @@ MACRO_SCOPE_HPP=include/nlohmann/detail/macro_scope.hpp

 # main target
 all:
-	@echo "amalgamate - amalgamate files single_include/nlohmann/json{,_fwd,_literals}.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"
@@ -87,10 +88,10 @@ 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) $(AMALGAMATED_LITERALS_FILE) docs/mkdocs/docs/examples/*.cpp docs/mkdocs/docs/examples/*.hpp
+	$(ASTYLE) --project=tools/astyle/.astylerc $(SRCS) $(TESTS_SRCS) $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_LITERALS_FILE) $(AMALGAMATED_VIEW_FILE) docs/mkdocs/docs/examples/*.cpp docs/mkdocs/docs/examples/*.hpp

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

 # call the amalgamation tool for json.hpp
@@ -105,6 +106,9 @@ $(AMALGAMATED_FWD_FILE): $(SRCS)
 $(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
 # regenerate nlohmann_json.natvis from the ABI tags and version in include/nlohmann/detail/abi_macros.hpp
 natvis:
 	python3 tools/generate_natvis/generate_natvis.py .
@@ -129,13 +133,16 @@ 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)
@@ -181,7 +188,7 @@ 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) $(AMALGAMATED_LITERALS_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
@@ -191,11 +198,13 @@ release: include.zip json.tar.xz
 	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
 	cp $(AMALGAMATED_LITERALS_FILE) release_files
-	mv $(AMALGAMATED_FILE).asc $(AMALGAMATED_FWD_FILE).asc $(AMALGAMATED_LITERALS_FILE).asc json.tar.xz json.tar.xz.asc include.zip include.zip.asc 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 $$(find . -type f -not -name '*.asc' | sed 's|^\./||' | sort) > hashes.txt


@@ -1188,6 +1188,14 @@ 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).
@@ -1394,7 +1402,8 @@ THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR I
 - 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 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 and its table of powers of five 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 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.

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

@@ -8,24 +8,24 @@ set(N 10)
 include(FindPython3)
 find_package(Python3 COMPONENTS Interpreter)

-find_program(CLANG_TOOL NAMES clang++-HEAD clang++ clang++-20 clang++-19 clang++-18 clang++-17 clang++-16 clang++-15 clang++-14 clang++-13 clang++-12 clang++-11 clang++)
+find_program(CLANG_TOOL NAMES clang++-HEAD clang++ clang++-22 clang++-21 clang++-20 clang++-19 clang++-18 clang++-17 clang++-16 clang++-15 clang++-14 clang++-13 clang++-12 clang++-11 clang++)
 execute_process(COMMAND ${CLANG_TOOL} --version OUTPUT_VARIABLE CLANG_TOOL_VERSION ERROR_VARIABLE CLANG_TOOL_VERSION)
 string(REGEX MATCH "[0-9]+(\\.[0-9]+)+" CLANG_TOOL_VERSION "${CLANG_TOOL_VERSION}")
 message(STATUS "🔖 Clang ${CLANG_TOOL_VERSION} (${CLANG_TOOL})")

-find_program(CLANG_TIDY_TOOL NAMES clang-tidy-20 clang-tidy-19 clang-tidy-18 clang-tidy-17 clang-tidy-16 clang-tidy-15 clang-tidy-14 clang-tidy-13 clang-tidy-12 clang-tidy-11 clang-tidy)
+find_program(CLANG_TIDY_TOOL NAMES clang-tidy-22 clang-tidy-21 clang-tidy-20 clang-tidy-19 clang-tidy-18 clang-tidy-17 clang-tidy-16 clang-tidy-15 clang-tidy-14 clang-tidy-13 clang-tidy-12 clang-tidy-11 clang-tidy)
 execute_process(COMMAND ${CLANG_TIDY_TOOL} --version OUTPUT_VARIABLE CLANG_TIDY_TOOL_VERSION ERROR_VARIABLE CLANG_TIDY_TOOL_VERSION)
 string(REGEX MATCH "[0-9]+(\\.[0-9]+)+" CLANG_TIDY_TOOL_VERSION "${CLANG_TIDY_TOOL_VERSION}")
 message(STATUS "🔖 Clang-Tidy ${CLANG_TIDY_TOOL_VERSION} (${CLANG_TIDY_TOOL})")

 message(STATUS "🔖 CMake ${CMAKE_VERSION} (${CMAKE_COMMAND})")

-find_program(GCC_TOOL NAMES g++-latest g++-HEAD g++ g++-15 g++-14 g++-13 g++-12 g++-11 g++-10)
+find_program(GCC_TOOL NAMES g++-latest g++-HEAD g++ g++-16 g++-15 g++-14 g++-13 g++-12 g++-11 g++-10)
 execute_process(COMMAND ${GCC_TOOL} --version OUTPUT_VARIABLE GCC_TOOL_VERSION ERROR_VARIABLE GCC_TOOL_VERSION)
 string(REGEX MATCH "[0-9]+(\\.[0-9]+)+" GCC_TOOL_VERSION "${GCC_TOOL_VERSION}")
 message(STATUS "🔖 GCC ${GCC_TOOL_VERSION} (${GCC_TOOL})")

-find_program(GCOV_TOOL NAMES gcov-HEAD gcov gcov-15 gcov-14 gcov-13 gcov-12 gcov-11 gcov-10)
+find_program(GCOV_TOOL NAMES gcov-HEAD gcov gcov-16 gcov-15 gcov-14 gcov-13 gcov-12 gcov-11 gcov-10)
 execute_process(COMMAND ${GCOV_TOOL} --version OUTPUT_VARIABLE GCOV_TOOL_VERSION ERROR_VARIABLE GCOV_TOOL_VERSION)
 string(REGEX MATCH "[0-9]+(\\.[0-9]+)+" GCOV_TOOL_VERSION "${GCOV_TOOL_VERSION}")
 message(STATUS "🔖 GCOV ${GCOV_TOOL_VERSION} (${GCOV_TOOL})")
@@ -396,10 +396,11 @@ list(FILTER INDENT_FILES EXCLUDE REGEX "/tests/thirdparty/|/tests/abi/include/nl
 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~ ${include_dir}/json_literals.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 cp ${PROJECT_SOURCE_DIR}/BUILD.bazel ${PROJECT_SOURCE_DIR}/BUILD.bazel~

    COMMAND ${Python3_EXECUTABLE} -mvenv venv_astyle
@@ -409,12 +410,14 @@ 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 cp ${PROJECT_SOURCE_DIR}/include/nlohmann/json_literals.hpp ${include_dir}/json_literals.hpp
-    COMMAND venv_astyle/bin/astyle --project=tools/astyle/.astylerc --suffix=none ${include_dir}/json.hpp ${include_dir}/json_fwd.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 ${CMAKE_COMMAND} -P ${PROJECT_SOURCE_DIR}/cmake/scripts/gen_bazel_build_file.cmake

    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 diff ${PROJECT_SOURCE_DIR}/BUILD.bazel~ ${PROJECT_SOURCE_DIR}/BUILD.bazel

    COMMAND venv_astyle/bin/astyle --project=tools/astyle/.astylerc --suffix=orig ${INDENT_FILES}
@@ -2,7 +2,6 @@
 # -Wno-c++98-compat               The library targets C++11.
 # -Wno-c++98-compat-pedantic      The library targets C++11.
 # -Wno-deprecated-declarations    The library contains annotations for deprecated functions.
-# -Wno-extra-semi-stmt            The library uses assert which triggers this warning.
 # -Wno-padded                     We do not care about padding warnings.
 # -Wno-covered-switch-default     All switches list all cases and a default case.
 # -Wno-c2y-extensions             Clang 22.1 diagnoses __COUNTER__ as a C2y extension, also in
@@ -20,7 +19,6 @@ set(CLANG_CXXFLAGS
    -Wno-c++98-compat
    -Wno-c++98-compat-pedantic
    -Wno-deprecated-declarations
-    -Wno-extra-semi-stmt
    -Wno-padded
    -Wno-covered-switch-default
    -Wno-c2y-extensions
@@ -1,4 +1,4 @@
-# Warning flags determined for GCC 15.1.0 with https://github.com/nlohmann/gcc_flags:
+# Warning flags determined for GCC 16.2.0 with https://github.com/nlohmann/gcc_flags:
 # Ignored GCC warnings:
 # -Wno-abi-tag           We do not care about ABI tags.
 # -Wno-aggregate-return  The library uses aggregate returns.
@@ -16,6 +16,8 @@ set(GCC_CXXFLAGS
    --extra-warnings
    -W
    -WNSObject-attribute
+    -Wabbreviated-auto-in-template-arg
+    -Wabi
    -Wno-abi-tag
    -Waddress
    -Waddress-of-packed-member
@@ -64,6 +66,7 @@ set(GCC_CXXFLAGS
    -Wanalyzer-tainted-divisor
    -Wanalyzer-tainted-offset
    -Wanalyzer-tainted-size
+    -Wanalyzer-throw-of-unexpected-type
    -Wanalyzer-too-complex
    -Wanalyzer-undefined-behavior-ptrdiff
    -Wanalyzer-undefined-behavior-strtok
@@ -80,10 +83,13 @@ set(GCC_CXXFLAGS
    -Warith-conversion
    -Warray-bounds=2
    -Warray-compare
+    -Warray-parameter
    -Warray-parameter=2
    -Wattribute-alias=2
    -Wattribute-warning
    -Wattributes
+    -Wauto-profile
+    -Wbidi-chars=any
    -Wbool-compare
    -Wbool-operation
    -Wbuiltin-declaration-mismatch
@@ -99,6 +105,7 @@ set(GCC_CXXFLAGS
    -Wc++20-compat
    -Wc++20-extensions
    -Wc++23-extensions
+    -Wc++26-compat
    -Wc++26-extensions
    -Wc++2a-compat
    -Wcalloc-transposed-args
@@ -142,6 +149,7 @@ set(GCC_CXXFLAGS
    -Wdeprecated-enum-enum-conversion
    -Wdeprecated-enum-float-conversion
    -Wdeprecated-literal-operator
+    -Wdeprecated-openmp
    -Wdeprecated-variadic-comma-omission
    -Wdisabled-optimization
    -Wdiv-by-zero
@@ -156,21 +164,18 @@ set(GCC_CXXFLAGS
    -Wenum-conversion
    -Wexceptions
    -Wexpansion-to-defined
+    -Wexperimental-fmv-target
+    -Wexpose-global-module-tu-local
+    -Wexternal-tu-local
    -Wextra
    -Wextra-semi
    -Wflex-array-member-not-at-end
    -Wfloat-conversion
    -Wfloat-equal
-    -Wformat -Wformat-contains-nul
-    -Wformat -Wformat-diag
-    -Wformat -Wformat-extra-args
-    -Wformat -Wformat-nonliteral
-    -Wformat -Wformat-overflow=2
-    -Wformat -Wformat-security
-    -Wformat -Wformat-signedness
-    -Wformat -Wformat-truncation=2
-    -Wformat -Wformat-y2k
-    -Wformat -Wformat-zero-length
+    -Wformat-diag
+    -Wformat-overflow=2
+    -Wformat-signedness
+    -Wformat-truncation=2
    -Wformat=2
    -Wframe-address
    -Wfree-nonheap-object
@@ -197,6 +202,8 @@ set(GCC_CXXFLAGS
    -Winvalid-offsetof
    -Winvalid-pch
    -Winvalid-utf8
+    -Wkeyword-macro
+    -Wleading-whitespace=spaces
    -Wliteral-suffix
    -Wlogical-not-parentheses
    -Wlogical-op
@@ -227,6 +234,7 @@ set(GCC_CXXFLAGS
    -Wnarrowing
    -Wnoexcept
    -Wnoexcept-type
+    -Wnon-c-typedef-for-linkage
    -Wnon-template-friend
    -Wnon-virtual-dtor
    -Wnonnull
@@ -269,6 +277,8 @@ set(GCC_CXXFLAGS
    -Wscalar-storage-order
    -Wself-move
    -Wsequence-point
+    -Wsfinae-incomplete
+    -Wsfinae-incomplete=2
    -Wshadow=compatible-local
    -Wshadow=global
    -Wshadow=local
@@ -289,6 +299,7 @@ set(GCC_CXXFLAGS
    -Wstrict-aliasing=3
    -Wstrict-null-sentinel
    -Wstrict-overflow
+    -Wstrict-overflow=5
    -Wstring-compare
    -Wstringop-overflow
    -Wstringop-overflow=4
@@ -333,8 +344,8 @@ set(GCC_CXXFLAGS
    -Wunreachable-code
    -Wunsafe-loop-optimizations
    -Wunused
-    -Wunused-but-set-parameter
-    -Wunused-but-set-variable
+    -Wunused-but-set-parameter=3
+    -Wunused-but-set-variable=3
    -Wunused-const-variable=2
    -Wunused-function
    -Wunused-label
@@ -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 +128,56 @@ 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::is_discarded', 'Method', 'api/basic_json_document/is_discarded/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::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::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::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::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::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[]/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 ('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_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 +211,8 @@ 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_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 +242,7 @@ 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');
@@ -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

@@ -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.
@@ -115,6 +115,7 @@ 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

@@ -80,6 +80,7 @@ Logarithmic in the size of the JSON object.

 - [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

@@ -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.
@@ -84,6 +84,7 @@ Logarithmic in the size of the JSON object.

 - [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

@@ -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

@@ -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).
@@ -257,6 +257,8 @@ 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

@@ -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.
@@ -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.
@@ -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 +1,56 @@
+# <small>nlohmann::</small>basic_json_document
+
+<small>Defined in header `<nlohmann/json_view.hpp>`</small>
+
+```cpp
+template<typename BasicJsonType>
+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.
+
+## 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`.
+
+## Specializations
+
+- [**json_document**](../json_document.md) - documents of the default specialization [`json`](../json.md)
+- [**ordered_json_document**](../ordered_json_document.md) - 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>`)
+- **value_t** - the JSON type enumeration, see [`basic_json::value_t`](../basic_json/value_t.md)
+
+## Member functions
+
+- [(constructor)](basic_json_document.md)
+- [**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
+- [**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
+
+## 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 +1,50 @@
+# <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 +1,139 @@
+# <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
+- [`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 +1,76 @@
+# <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
+
+## 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 +1,58 @@
+# <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 +1,90 @@
+# <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;
+```
+
+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`.
+
+## Parameters
+
+`key` (in)
+:   object key of the element to access
+
+`idx` (in)
+:   index of the element to access
+
+## Return value
+
+1. the value of the first member with key `key`
+2. the element at index `idx`
+
+## 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()`.
+
+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.
+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).
+
+## 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.
+
+## Examples
+
+??? example
+
+    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"
+    ```
+
+## 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`
+
+## 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 +1,64 @@
+# <small>nlohmann::basic_json_view::</small>contains
+
+```cpp
+bool contains(string_view_t key) const;
+bool contains(const char* key) const;
+bool contains(const string_t& key) const;
+```
+
+Checks whether the value is an object with a member with key `key`.
+
+## Parameters
+
+`key` (in)
+:   key value to check its existence
+
+## Return value
+
+`#!cpp true` if the value is an object and has a member with key `key`, `#!cpp false` 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.
+
+## Notes
+
+This method 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).
+
+## Examples
+
+??? example
+
+    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"
+    ```
+
+## See also
+
+- [find](find.md) - find a value in an object
+- [count](count.md) - returns the number of occurrences of a key
+- [`BasicJsonType::contains`](../basic_json/contains.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,66 @@
+# <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.
+
+## 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 +1,61 @@
+# <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 +1,63 @@
+# <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.
+
+## 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 +1,107 @@
+# <small>nlohmann::</small>basic_json_view
+
+<small>Defined in header `<nlohmann/json_view.hpp>`</small>
+
+```cpp
+template<typename BasicJsonType>
+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, and [`materialize()`](materialize.md) to build the `BasicJsonType` value of a subtree on
+demand. It does not (yet) provide `get<T>()`, JSON Pointer support, `dump()`, or comparison.
+
+## 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.
+
+## 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)
+
+## 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)
+
+## 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
+- [**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
+
+- [**materialize**](materialize.md) - build the `BasicJsonType` value of this subtree
+
+### 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.
@@ -0,0 +1,46 @@
+# <small>nlohmann::basic_json_view::</small>is_primitive
+
+```cpp
+bool is_primitive() const noexcept;
+```
+
+This function returns `#!cpp true` if and only if the value is primitive, i.e. `#!json null`, a boolean, a number, or a string. It is defined as `#!cpp is_null() || is_string() || is_boolean() || is_number()`.
+
+## Return value
+
+`#!cpp true` if the type is primitive, `#!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 (the complement of this function, for a
+  non-discarded view)
+- [`BasicJsonType::is_primitive`](../basic_json/is_primitive.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_string
+
+```cpp
+bool is_string() const noexcept;
+```
+
+This function returns `#!cpp true` if and only if the value is a string.
+
+## Return value
+
+`#!cpp true` if the type is a string, `#!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
+
+- [source_offset](source_offset.md) - byte offset of this value in the document's source text
+- [`BasicJsonType::is_string`](../basic_json/is_string.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_structured
+
+```cpp
+bool is_structured() const noexcept;
+```
+
+This function returns `#!cpp true` if and only if the value is structured, i.e. an array or an object. It is defined as `#!cpp is_array() || is_object()`.
+
+## Return value
+
+`#!cpp true` if the type is structured, `#!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_primitive](is_primitive.md) - return whether the type is primitive
+- [size](size.md), [empty](empty.md) - the number of elements, and whether there are none
+- [`BasicJsonType::is_structured`](../basic_json/is_structured.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,86 @@
+# <small>nlohmann::basic_json_view::</small>items
+
+```cpp
+/* unspecified */ items() const noexcept;
+```
+
+Returns a range of [`item`](index.md#member-types) values -- (key, value) pairs -- for use in range-based for loops.
+The key of an array element is its index, converted to a string, as for
+[`BasicJsonType::items()`](../basic_json/items.md).
+
+The returned type is not part of the public API and may change between versions; use a range-based for loop (see the
+example), or `#!cpp decltype(v.items())` if you need to name it.
+
+```cpp
+for (const auto& item : v.items())
+{
+    std::cout << "key: " << item.key() << ", value: " << item.value() << '\n';
+}
+```
+
+On C++17, `item` also supports [structured bindings](https://en.cppreference.com/w/cpp/language/structured_binding):
+
+```cpp
+for (const auto [key, value] : v.items())
+{
+    std::cout << "key: " << key << ", value: " << value << '\n';
+}
+```
+
+Note the `#!cpp const auto` (by value), not `#!cpp const auto&`: unlike `BasicJsonType::items()`, whose elements are
+references into an existing object, a view's `item` is produced on the fly for each step of the iteration, so there
+is nothing for a reference to bind to.
+
+## Return value
+
+A range whose iterators dereference to [`item`](index.md#member-types) and whose `#!cpp begin()`/`#!cpp end()` are
+equivalent to [`basic_json_view::begin()`](begin.md)/[`end()`](end.md), in document order.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Notes
+
+As for [`begin()`](begin.md)/[`end()`](end.md), `items()` visits **every** member of an object, 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 resolve to the *first* member with a given key. See the
+[Notes on duplicate keys](operator[].md#notes) of `operator[]`.
+
+!!! danger "Lifetime issues"
+
+    As for `BasicJsonType::items()`, calling `items()` on a temporary view (or a temporary document) is dangerous:
+    the range refers back to the document, so the document must outlive the loop. See
+    [#2040](https://github.com/nlohmann/json/issues/2040) for the `BasicJsonType` background.
+
+## Examples
+
+??? example
+
+    The example below shows a settings object whose source text records every update to a key as a duplicate
+    member, in the order they happened. `items()` walks all of them, so the update history is visible, while
+    [`operator[]`](operator[].md) only ever sees the *first* one and [`materialize()`](materialize.md) -- like
+    [`BasicJsonType::parse()`](../basic_json/parse.md) -- keeps only the *last*.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__items.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__items.output"
+    ```
+
+## See also
+
+- [begin](begin.md), [end](end.md) - the iterators `items()` is built on
+- [`BasicJsonType::items`](../basic_json/items.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,69 @@
+# <small>nlohmann::basic_json_view::</small>materialize
+
+```cpp
+BasicJsonType materialize() const;
+```
+
+Builds the `BasicJsonType` value of this subtree: the value [`BasicJsonType::parse()`](../basic_json/parse.md) would
+have produced for the same source text, allocated for the first time by this call.
+
+## Return value
+
+The `BasicJsonType` value of this subtree, or a discarded `BasicJsonType` value (`#!cpp BasicJsonType(value_t::discarded)`)
+if the view is [discarded](is_discarded.md).
+
+## Exception safety
+
+Strong guarantee: if an exception is thrown, there are no changes to the view or the document it refers to (nothing
+about either is mutated by this function).
+
+## Exceptions
+
+May throw `#!cpp std::bad_alloc` (via `BasicJsonType`'s allocator) if constructing the result fails.
+
+## Complexity
+
+Linear in the size of the subtree.
+
+## Notes
+
+`materialize()` replays the subtree through the same SAX builder [`BasicJsonType::parse()`](../basic_json/parse.md)
+uses internally, so the result matches it exactly -- including, for an object, that a repeated key keeps only its
+last value. The replay is iterative, so it is not limited by the call stack the way a naive recursive conversion
+would be; the JSON nesting depth is limited only by available memory, as for `BasicJsonType::parse()` itself.
+
+Unlike parsing with [`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) enabled, the values
+produced by `materialize()` do not carry source positions: there is no lexer run during the replay to record them.
+
+Calling `materialize()` on the same view repeatedly builds a new, independent `BasicJsonType` value each time; it
+never caches the result.
+
+## Examples
+
+??? example
+
+    The example below skips messages that are not useful -- a discarded value, or an empty array -- using only
+    [`is_array()`](is_array.md) and [`empty()`](empty.md), and calls `materialize()` only for the messages that are
+    actually used, so no `BasicJsonType` value (and none of its per-element allocations) is ever built for the
+    skipped ones.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__materialize.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__materialize.output"
+    ```
+
+## See also
+
+- [root](../basic_json_document/root.md) - the view of a document's root value
+- [`BasicJsonType::parse`](../basic_json/parse.md) - build a `BasicJsonType` value directly from a JSON text
+- [`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) - source positions on parsed values (not
+  produced by `materialize()`)
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,105 @@
+# <small>nlohmann::basic_json_view::</small>operator[]
+
+```cpp
+// (1)
+basic_json_view operator[](string_view_t key) const;
+basic_json_view operator[](const char* key) const;
+basic_json_view operator[](const string_t& key) const;
+
+// (2)
+basic_json_view operator[](size_type idx) const;
+basic_json_view operator[](int idx) const;
+```
+
+1. Returns the value of the object member with key `key` -- the first one, should the key occur more than once (see
+   the [Notes](#notes) below) -- or a [discarded](is_discarded.md) view if there is no such member.
+2. Returns the array element at index `idx`, or a [discarded](is_discarded.md) view if `idx` is out of range. (The
+   `#!cpp int` overload only exists so that an integer literal is not ambiguous between this overload and 1.)
+
+## Parameters
+
+`key` (in)
+:   object key of the element to access
+
+`idx` (in)
+:   index of the element to access
+
+## Return value
+
+1. the value of the first member with key `key`, or a discarded view if `#!cpp is_object()` is `#!cpp false` or no
+   member has this key
+2. the element at index `idx`, or a discarded view if `#!cpp is_array()` is `#!cpp false` or `#!cpp idx >= size()`
+
+## 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. Throws [`type_error.305`](../../home/exceptions.md#jsonexceptiontype_error305) if the value is not an object --
+   the same exception, with the same message, that the **const** overload of
+   [`BasicJsonType::operator[]`](../basic_json/operator%5B%5D.md) throws for a string argument on a non-object value.
+2. Throws [`type_error.305`](../../home/exceptions.md#jsonexceptiontype_error305) if the value is not an array --
+   the same exception, with the same message, that the **const** overload of
+   [`BasicJsonType::operator[]`](../basic_json/operator%5B%5D.md) throws for a numeric argument on a non-array value.
+
+Neither exception carries 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, so a key of a
+   different length than `key` is rejected without touching the source text.
+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).
+
+## Notes
+
+Unlike `BasicJsonType::operator[]`, which is undefined behavior (guarded by a
+[runtime assertion](../../features/assertions.md)) for a missing key on a **const** value, this operator always
+returns a safe, testable result: a [discarded](is_discarded.md) view, which is `#!cpp false` in a boolean context.
+There is also no non-const overload that inserts a missing key or extends an array -- a view never modifies the
+document.
+
+!!! info "Duplicate keys"
+
+    If the source text has an object with a duplicate key, `#!cpp operator[]` (and [`at`](at.md), [`find`](find.md),
+    [`contains`](contains.md), [`count`](count.md)) all resolve to the *first* member with that key, because a
+    lookup can stop as soon as it finds a match. This is different from
+    [`materialize()`](materialize.md) (and [`BasicJsonType::parse()`](../basic_json/parse.md)), which replay every
+    member in order and so end up keeping the *last* value for a repeated key -- there is no reason for them to stop
+    early. [`begin()`](begin.md)/[`end()`](end.md) and [`items()`](items.md) iterate over *all* members, including
+    duplicates, in document order. See the example below and [`size()`](size.md#notes).
+
+## Examples
+
+??? example
+
+    The example below reads a couple of fields out of a batch of user records without ever materializing a full
+    `BasicJsonType` value for the batch. `operator[]` is used both to look up an optional object member and to index
+    into an array -- in both cases, a missing value comes back as a discarded view that can be tested with a plain
+    `#!cpp if`, instead of relying on undefined behavior.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__operator[].cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__operator[].output"
+    ```
+
+## See also
+
+- [at](at.md) - access specified element with bounds checking (throws instead of returning a discarded view)
+- [front](front.md), [back](back.md) - access the first or last element
+- [find](find.md), [contains](contains.md) - look up a member without throwing
+- [`BasicJsonType::operator[]`](../basic_json/operator%5B%5D.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>operator bool
+
+```cpp
+explicit operator bool() const noexcept;
+```
+
+Returns whether this view refers to a value, i.e. the negation of [`is_discarded()`](is_discarded.md). Being
+`#!cpp explicit`, this conversion is only considered in a boolean context (`#!cpp if (v)`, `#!cpp !v`, `#!cpp v &&
+...`), not for implicit conversions to other types.
+
+## Return value
+
+`#!cpp true` if the view refers to a value, `#!cpp false` if it is [discarded](is_discarded.md).
+
+## 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_discarded](is_discarded.md) - return whether the view is invalid
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,66 @@
+# <small>nlohmann::basic_json_view::</small>size
+
+```cpp
+size_type size() const noexcept;
+```
+
+Returns the number of elements, as [`BasicJsonType::size()`](../basic_json/size.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                  | `0`                          |
+| discarded             | `0`                          |
+| boolean               | `1`                          |
+| string                | `1`                          |
+| number                | `1`                          |
+| object                | number of key/value pairs    |
+| array                 | number of elements           |
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant: for an object or array, the element count is stored in the index, not counted on demand.
+
+## Notes
+
+As for [`BasicJsonType::size()`](../basic_json/size.md), this does not return the length of a string value -- it is
+`1` for a string, regardless of its length.
+
+If the source text has an object with a duplicate key, every occurrence counts towards its `size()` -- unlike
+[`materialize()`](materialize.md) (and [`BasicJsonType::parse()`](../basic_json/parse.md)), which keeps only the last
+value for a repeated key. This means `#!cpp v.size()` can be larger than `#!cpp v.materialize().size()`. See the
+[Notes on duplicate keys](operator[].md#notes) of `operator[]` for why lookups and iteration disagree on how many
+members there are.
+
+## Examples
+
+??? example
+
+    The example below uses `size()` and [`empty()`](empty.md) 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
+
+- [empty](empty.md) - return whether the value has no elements
+- [`BasicJsonType::size`](../basic_json/size.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>source_offset
+
+```cpp
+std::size_t source_offset() const noexcept;
+```
+
+Returns the byte offset of this value in the document's [`source()`](../basic_json_document/source.md) text, without
+materializing anything.
+
+## Return value
+
+- For a string with no escapes, a number, `#!json true`/`#!json false`/`#!json null`, an array, or an object: the
+  byte offset of the first byte of the value's token (for a string: the first byte after the opening quote) in
+  [`source()`](../basic_json_document/source.md).
+- `#!cpp static_cast<std::size_t>(-1)` for a [discarded](is_discarded.md) view, and for a string that contains
+  escapes -- such a string was decoded once into the document's own buffer, so there is no single byte range in
+  `source()` left to point at.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Notes
+
+This is a raw offset, not a length: the API does not (yet) expose how many bytes the token occupies in the source
+text, so `source_offset()` alone is enough to report *where* a value came from (for an error message, for syntax
+highlighting, ...) but not to slice its exact text back out of [`source()`](../basic_json_document/source.md) for a
+string, whose token length is not the same as its decoded [`size()`](size.md).
+
+## Examples
+
+??? example
+
+    ```cpp
+    --8<-- "examples/basic_json_view__source_offset.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__source_offset.output"
+    ```
+
+## See also
+
+- [source](../basic_json_document/source.md) - the parsed text
+- [is_string](is_string.md) - return whether the value is a string
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,53 @@
+# <small>nlohmann::basic_json_view::</small>type
+
+```cpp
+value_t type() const noexcept;
+```
+
+Returns the type of the value this view refers to, as a value from the [`value_t`](../basic_json/value_t.md)
+enumeration -- the same enumeration [`BasicJsonType::type()`](../basic_json/type.md) uses.
+
+## Return value
+
+The type of the value; `#!cpp value_t::discarded` for a [discarded](is_discarded.md) view.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Notes
+
+Unlike [`BasicJsonType::type()`](../basic_json/type.md), this function can never return `#!cpp value_t::binary`: a
+JSON text has no binary values, so `type()` only distinguishes the eight ordinary JSON value types (plus
+`#!cpp discarded`).
+
+## 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_null](is_null.md), [is_boolean](is_boolean.md), [is_number](is_number.md), [is_string](is_string.md),
+  [is_array](is_array.md), [is_object](is_object.md) - type-specific predicates built on `type()`
+- [`BasicJsonType::type`](../basic_json/type.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,63 @@
+# <small>nlohmann::basic_json_view::</small>type_name
+
+```cpp
+const char* type_name() const noexcept;
+```
+
+Returns the type name as string to be used in error messages -- usually to indicate that a function was called on a
+wrong JSON type. Identical to [`BasicJsonType::type_name()`](../basic_json/type_name.md), including the extra
+`#!cpp "discarded"` return value for a [discarded](is_discarded.md) view (`BasicJsonType::type_name()` produces the
+same string for a discarded `BasicJsonType` value).
+
+## Return value
+
+a string representation of the type ([`value_t`](../basic_json/value_t.md)):
+
+| Value type                                         | return value  |
+|-----------------------------------------------------|---------------|
+| `#!json null`                                        | `"null"`      |
+| boolean                                              | `"boolean"`   |
+| string                                               | `"string"`    |
+| number (integer, unsigned integer, floating-point)   | `"number"`    |
+| object                                               | `"object"`    |
+| array                                                | `"array"`     |
+| discarded                                            | `"discarded"` |
+
+`type_name()` never returns `#!cpp "binary"`, since a JSON text has no binary values (see
+[`is_binary()`](is_binary.md)); it also never returns `#!cpp "invalid"`, since a view's `#!cpp kind` always comes
+from a value the parser actually produced.
+
+## Exception safety
+
+No-throw guarantee: this function never throws exceptions.
+
+## Complexity
+
+Constant.
+
+## Examples
+
+??? example
+
+    The example below reports why some parsed messages were rejected, using only `type_name()` -- no
+    `BasicJsonType` value is ever built for the ones that are wrong, and the message text matches what
+    [`BasicJsonType::type_name()`](../basic_json/type_name.md) would produce for the same value.
+
+    ```cpp
+    --8<-- "examples/basic_json_view__type_name.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/basic_json_view__type_name.output"
+    ```
+
+## See also
+
+- [type](type.md) - return the type of the value
+- [`BasicJsonType::type_name`](../basic_json/type_name.md) - the corresponding function of `basic_json`
+
+## Version history
+
+- Added in version 3.13.0.
@@ -0,0 +1,35 @@
+# <small>nlohmann::</small>json_document
+
+<small>Defined in header `<nlohmann/json_view.hpp>`</small>
+
+```cpp
+using json_document = basic_json_document<json>;
+```
+
+This type is a [`basic_json_document`](basic_json_document/index.md) of the default [`json`](json.md)
+specialization.
+
+## Examples
+
+??? example
+
+    The example below demonstrates how to use the type `nlohmann::json_document`.
+
+    ```cpp
+    --8<-- "examples/json_document.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/json_document.output"
+    ```
+
+## See also
+
+- [json_view](json_view.md) - a view of a value of a `json_document`
+- [ordered_json_document](ordered_json_document.md) - the corresponding document for `ordered_json`
+
+## Version history
+
+Since version 3.13.0.
@@ -0,0 +1,34 @@
+# <small>nlohmann::</small>json_view
+
+<small>Defined in header `<nlohmann/json_view.hpp>`</small>
+
+```cpp
+using json_view = basic_json_view<json>;
+```
+
+This type is a [`basic_json_view`](basic_json_view/index.md) of a value of a [`json_document`](json_document.md).
+
+## Examples
+
+??? example
+
+    The example below demonstrates how to use the type `nlohmann::json_view`.
+
+    ```cpp
+    --8<-- "examples/json_view.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/json_view.output"
+    ```
+
+## See also
+
+- [json_document](json_document.md) - the document type this view refers into
+- [ordered_json_view](ordered_json_view.md) - the corresponding view for `ordered_json_document`
+
+## Version history
+
+Since version 3.13.0.
@@ -0,0 +1,38 @@
+# <small>nlohmann::</small>ordered_json_document
+
+<small>Defined in header `<nlohmann/json_view.hpp>`</small>
+
+```cpp
+using ordered_json_document = basic_json_document<ordered_json>;
+```
+
+This type is a [`basic_json_document`](basic_json_document/index.md) of the [`ordered_json`](ordered_json.md)
+specialization: [`materialize()`](basic_json_view/materialize.md) on one of its views preserves the insertion order
+of object keys, instead of sorting them like [`json_document`](json_document.md) does.
+
+## Examples
+
+??? example
+
+    The example below demonstrates how `ordered_json_document` preserves the insertion order of object keys when
+    materializing.
+
+    ```cpp
+    --8<-- "examples/ordered_json_document.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/ordered_json_document.output"
+    ```
+
+## See also
+
+- [ordered_json_view](ordered_json_view.md) - a view of a value of an `ordered_json_document`
+- [json_document](json_document.md) - the corresponding document for the default `json` specialization
+- [Object Order](../features/object_order.md)
+
+## Version history
+
+Since version 3.13.0.
@@ -0,0 +1,35 @@
+# <small>nlohmann::</small>ordered_json_view
+
+<small>Defined in header `<nlohmann/json_view.hpp>`</small>
+
+```cpp
+using ordered_json_view = basic_json_view<ordered_json>;
+```
+
+This type is a [`basic_json_view`](basic_json_view/index.md) of a value of an
+[`ordered_json_document`](ordered_json_document.md).
+
+## Examples
+
+??? example
+
+    The example below demonstrates how to use the type `nlohmann::ordered_json_view`.
+
+    ```cpp
+    --8<-- "examples/ordered_json_view.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/ordered_json_view.output"
+    ```
+
+## See also
+
+- [ordered_json_document](ordered_json_document.md) - the document type this view refers into
+- [json_view](json_view.md) - the corresponding view for `json_document`
+
+## Version history
+
+Since version 3.13.0.
@@ -0,0 +1,19 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+#include <nlohmann/json_view.hpp>
+
+using json_document = nlohmann::json_document;
+
+int main()
+{
+    std::cout << std::boolalpha;
+
+    // accept() behaves exactly like basic_json::accept(): the same inputs are
+    // accepted or rejected, with the same ignore_comments/ignore_trailing_commas
+    // options
+    std::cout << json_document::accept(R"({"a": 1})") << '\n';
+    std::cout << json_document::accept(R"({"a": 1,})") << '\n'; // trailing comma: rejected by default
+    std::cout << json_document::accept(R"({"a": 1,})", false, true) << '\n'; // ignore_trailing_commas
+
+    std::cout << (json_document::accept(R"({"a": 1})") == nlohmann::json::accept(R"({"a": 1})")) << '\n';
+}
--- a/Show More
+++ b/Show More