diff --git a/docs/mkdocs/docs/api/basic_json/accept.md b/docs/mkdocs/docs/api/basic_json/accept.md
index 77100a045..dac5f9f36 100644
--- a/docs/mkdocs/docs/api/basic_json/accept.md
+++ b/docs/mkdocs/docs/api/basic_json/accept.md
@@ -8,13 +8,7 @@ static bool accept(InputType&& i,
                    const bool ignore_trailing_commas = false);
 
 // (2)
-template<typename IteratorType>
-static bool accept(IteratorType first, IteratorType last,
-                   const bool ignore_comments = false,
-                   const bool ignore_trailing_commas = false);
-
-// (3)
-template<typename IteratorType, typename SentinelType>
+template<typename IteratorType, typename SentinelType = IteratorType>
 static bool accept(IteratorType first, SentinelType last,
                    const bool ignore_comments = false,
                    const bool ignore_trailing_commas = false);
@@ -23,14 +17,11 @@ static bool accept(IteratorType first, SentinelType last,
 Checks whether the input is valid JSON.
 
 1. Reads from a compatible input.
-2. Reads from a pair of character iterators (same type)
+2. Reads from a pair of character iterators, or an iterator and a sentinel of a different type (C++20 ranges support)
     
     The value_type of the iterator must be an integral type with a size of 1, 2, or 4 bytes, which will be interpreted
-    respectively as UTF-8, UTF-16, and UTF-32.
-3. Reads from an iterator and a sentinel (different types, C++20 ranges support)
-    
-    The value_type of the iterator must be an integral type with a size of 1, 2, or 4 bytes, which will be interpreted
-    respectively as UTF-8, UTF-16, and UTF-32. The sentinel type must be comparable to the iterator type with `operator!=`.
+    respectively as UTF-8, UTF-16, and UTF-32. If `SentinelType` differs from `IteratorType`, it must be comparable to
+    the iterator type with `operator!=`.
     
 Unlike the [`parse()`](parse.md) function, this function neither throws an exception in case of invalid JSON input
 (i.e., a parse error) nor creates diagnostic information.
@@ -55,7 +46,7 @@ Unlike the [`parse()`](parse.md) function, this function neither throws an excep
     - a pair of pointers such as `ptr` and `ptr + len`
 
 `SentinelType`
-:   a sentinel type compatible with `IteratorType` (different from `IteratorType` and comparable via `operator!=`), for instance.
+:   defaults to `IteratorType`; may be a different type comparable to `IteratorType` via `operator!=`, for instance.
 
     - a custom sentinel type for C++20 ranges
     - `std::counted_iterator` with a different sentinel type
@@ -128,7 +119,7 @@ A UTF-8 byte order mark is silently ignored.
 - Changed [runtime assertion](../../features/assertions.md) in case of `FILE*` null pointers to exception in version 3.12.0.
 - Added `ignore_trailing_commas` in version 3.13.0.
 - Extended container support (1) to include types with lvalue-only ADL `begin`/`end` (matching `std::begin`/`std::end` semantics) in version 3.13.0.
-- Added overload (3) for heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
+- Extended overload (2) to accept heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
 
 !!! warning "Deprecation"
 
diff --git a/docs/mkdocs/docs/api/basic_json/from_bjdata.md b/docs/mkdocs/docs/api/basic_json/from_bjdata.md
index 9c6768ef3..150f17aac 100644
--- a/docs/mkdocs/docs/api/basic_json/from_bjdata.md
+++ b/docs/mkdocs/docs/api/basic_json/from_bjdata.md
@@ -7,13 +7,7 @@ static basic_json from_bjdata(InputType&& i,
                               const bool strict = true,
                               const bool allow_exceptions = true);
 // (2)
-template<typename IteratorType>
-static basic_json from_bjdata(IteratorType first, IteratorType last,
-                              const bool strict = true,
-                              const bool allow_exceptions = true);
-
-// (3)
-template<typename IteratorType, typename SentinelType>
+template<typename IteratorType, typename SentinelType = IteratorType>
 static basic_json from_bjdata(IteratorType first, SentinelType last,
                               const bool strict = true,
                               const bool allow_exceptions = true);
@@ -22,8 +16,7 @@ static basic_json from_bjdata(IteratorType first, SentinelType last,
 Deserializes a given input to a JSON value using the BJData (Binary JData) serialization format.
 
 1. Reads from a compatible input.
-2. Reads from an iterator range.
-3. Reads from an iterator and a sentinel (different types, C++20 ranges support).
+2. Reads from an iterator range, or an iterator and a sentinel of a different type (C++20 ranges support).
 
 The exact mapping and its limitations are described on a [dedicated page](../../features/binary_formats/bjdata.md).
 
@@ -43,7 +36,8 @@ The exact mapping and its limitations are described on a [dedicated page](../../
 :   a compatible iterator type
 
 `SentinelType`
-:   a sentinel type compatible with `IteratorType` (different from `IteratorType` and comparable via `operator!=`), for instance a custom sentinel type for C++20 ranges
+:   defaults to `IteratorType`; may be a different type comparable to `IteratorType` via `operator!=`, for instance a
+    custom sentinel type for C++20 ranges
 
 ## Parameters
 
@@ -113,4 +107,4 @@ Linear in the size of the input.
 
 - Added in version 3.11.0.
 - Extended container support (1) to include types with lvalue-only ADL `begin`/`end` (matching `std::begin`/`std::end` semantics) in version 3.13.0.
-- Added overload (3) for heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
+- Extended overload (2) to accept heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
diff --git a/docs/mkdocs/docs/api/basic_json/from_bson.md b/docs/mkdocs/docs/api/basic_json/from_bson.md
index 5d9967c42..eb06a7177 100644
--- a/docs/mkdocs/docs/api/basic_json/from_bson.md
+++ b/docs/mkdocs/docs/api/basic_json/from_bson.md
@@ -7,13 +7,7 @@ static basic_json from_bson(InputType&& i,
                             const bool strict = true,
                             const bool allow_exceptions = true);
 // (2)
-template<typename IteratorType>
-static basic_json from_bson(IteratorType first, IteratorType last,
-                            const bool strict = true,
-                            const bool allow_exceptions = true);
-
-// (3)
-template<typename IteratorType, typename SentinelType>
+template<typename IteratorType, typename SentinelType = IteratorType>
 static basic_json from_bson(IteratorType first, SentinelType last,
                             const bool strict = true,
                             const bool allow_exceptions = true);
@@ -22,8 +16,7 @@ static basic_json from_bson(IteratorType first, SentinelType last,
 Deserializes a given input to a JSON value using the BSON (Binary JSON) serialization format.
 
 1. Reads from a compatible input.
-2. Reads from an iterator range.
-3. Reads from an iterator and a sentinel (different types, C++20 ranges support).
+2. Reads from an iterator range, or an iterator and a sentinel of a different type (C++20 ranges support).
 
 The exact mapping and its limitations are described on a [dedicated page](../../features/binary_formats/bson.md).
 
@@ -43,7 +36,8 @@ The exact mapping and its limitations are described on a [dedicated page](../../
 :   a compatible iterator type
 
 `SentinelType`
-:   a sentinel type compatible with `IteratorType` (different from `IteratorType` and comparable via `operator!=`), for instance a custom sentinel type for C++20 ranges
+:   defaults to `IteratorType`; may be a different type comparable to `IteratorType` via `operator!=`, for instance a
+    custom sentinel type for C++20 ranges
 
 ## Parameters
 
@@ -113,7 +107,7 @@ Linear in the size of the input.
 
 - Added in version 3.4.0.
 - Extended container support (1) to include types with lvalue-only ADL `begin`/`end` (matching `std::begin`/`std::end` semantics) in version 3.13.0.
-- Added overload (3) for heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
+- Extended overload (2) to accept heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
 
 !!! warning "Deprecation"
 
diff --git a/docs/mkdocs/docs/api/basic_json/from_cbor.md b/docs/mkdocs/docs/api/basic_json/from_cbor.md
index c9a326c96..3792307bd 100644
--- a/docs/mkdocs/docs/api/basic_json/from_cbor.md
+++ b/docs/mkdocs/docs/api/basic_json/from_cbor.md
@@ -9,14 +9,7 @@ static basic_json from_cbor(InputType&& i,
                             const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error);
 
 // (2)
-template<typename IteratorType>
-static basic_json from_cbor(IteratorType first, IteratorType last,
-                            const bool strict = true,
-                            const bool allow_exceptions = true,
-                            const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error);
-
-// (3)
-template<typename IteratorType, typename SentinelType>
+template<typename IteratorType, typename SentinelType = IteratorType>
 static basic_json from_cbor(IteratorType first, SentinelType last,
                             const bool strict = true,
                             const bool allow_exceptions = true,
@@ -26,8 +19,7 @@ static basic_json from_cbor(IteratorType first, SentinelType last,
 Deserializes a given input to a JSON value using the CBOR (Concise Binary Object Representation) serialization format.
 
 1. Reads from a compatible input.
-2. Reads from an iterator range.
-3. Reads from an iterator and a sentinel (different types, C++20 ranges support).
+2. Reads from an iterator range, or an iterator and a sentinel of a different type (C++20 ranges support).
 
 The exact mapping and its limitations are described on a [dedicated page](../../features/binary_formats/cbor.md).
 
@@ -47,7 +39,8 @@ The exact mapping and its limitations are described on a [dedicated page](../../
 :   a compatible iterator type
 
 `SentinelType`
-:   a sentinel type compatible with `IteratorType` (different from `IteratorType` and comparable via `operator!=`), for instance a custom sentinel type for C++20 ranges
+:   defaults to `IteratorType`; may be a different type comparable to `IteratorType` via `operator!=`, for instance a
+    custom sentinel type for C++20 ranges
 
 ## Parameters
 
@@ -124,7 +117,7 @@ Linear in the size of the input.
 - Added `allow_exceptions` parameter in version 3.2.0.
 - Added `tag_handler` parameter in version 3.9.0.
 - Extended container support (1) to include types with lvalue-only ADL `begin`/`end` (matching `std::begin`/`std::end` semantics) in version 3.13.0.
-- Added overload (3) for heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
+- Extended overload (2) to accept heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
 
 !!! warning "Deprecation"
 
diff --git a/docs/mkdocs/docs/api/basic_json/from_msgpack.md b/docs/mkdocs/docs/api/basic_json/from_msgpack.md
index 21876af72..dd7719804 100644
--- a/docs/mkdocs/docs/api/basic_json/from_msgpack.md
+++ b/docs/mkdocs/docs/api/basic_json/from_msgpack.md
@@ -7,13 +7,7 @@ static basic_json from_msgpack(InputType&& i,
                                const bool strict = true,
                                const bool allow_exceptions = true);
 // (2)
-template<typename IteratorType>
-static basic_json from_msgpack(IteratorType first, IteratorType last,
-                               const bool strict = true,
-                               const bool allow_exceptions = true);
-
-// (3)
-template<typename IteratorType, typename SentinelType>
+template<typename IteratorType, typename SentinelType = IteratorType>
 static basic_json from_msgpack(IteratorType first, SentinelType last,
                                const bool strict = true,
                                const bool allow_exceptions = true);
@@ -22,8 +16,7 @@ static basic_json from_msgpack(IteratorType first, SentinelType last,
 Deserializes a given input to a JSON value using the MessagePack serialization format.
 
 1. Reads from a compatible input.
-2. Reads from an iterator range.
-3. Reads from an iterator and a sentinel (different types, C++20 ranges support).
+2. Reads from an iterator range, or an iterator and a sentinel of a different type (C++20 ranges support).
 
 The exact mapping and its limitations are described on a [dedicated page](../../features/binary_formats/messagepack.md).
 
@@ -43,7 +36,8 @@ The exact mapping and its limitations are described on a [dedicated page](../../
 :   a compatible iterator type
 
 `SentinelType`
-:   a sentinel type compatible with `IteratorType` (different from `IteratorType` and comparable via `operator!=`), for instance a custom sentinel type for C++20 ranges
+:   defaults to `IteratorType`; may be a different type comparable to `IteratorType` via `operator!=`, for instance a
+    custom sentinel type for C++20 ranges
 
 ## Parameters
 
@@ -115,7 +109,7 @@ Linear in the size of the input.
 - Changed to consume input adapters, removed `start_index` parameter, and added `strict` parameter in version 3.0.0.
 - Added `allow_exceptions` parameter in version 3.2.0.
 - Extended container support (1) to include types with lvalue-only ADL `begin`/`end` (matching `std::begin`/`std::end` semantics) in version 3.13.0.
-- Added overload (3) for heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
+- Extended overload (2) to accept heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
 
 !!! warning "Deprecation"
 
diff --git a/docs/mkdocs/docs/api/basic_json/from_ubjson.md b/docs/mkdocs/docs/api/basic_json/from_ubjson.md
index 8a2d814ba..55c68c0ae 100644
--- a/docs/mkdocs/docs/api/basic_json/from_ubjson.md
+++ b/docs/mkdocs/docs/api/basic_json/from_ubjson.md
@@ -7,13 +7,7 @@ static basic_json from_ubjson(InputType&& i,
                               const bool strict = true,
                               const bool allow_exceptions = true);
 // (2)
-template<typename IteratorType>
-static basic_json from_ubjson(IteratorType first, IteratorType last,
-                              const bool strict = true,
-                              const bool allow_exceptions = true);
-
-// (3)
-template<typename IteratorType, typename SentinelType>
+template<typename IteratorType, typename SentinelType = IteratorType>
 static basic_json from_ubjson(IteratorType first, SentinelType last,
                               const bool strict = true,
                               const bool allow_exceptions = true);
@@ -22,8 +16,7 @@ static basic_json from_ubjson(IteratorType first, SentinelType last,
 Deserializes a given input to a JSON value using the UBJSON (Universal Binary JSON) serialization format.
 
 1. Reads from a compatible input.
-2. Reads from an iterator range.
-3. Reads from an iterator and a sentinel (different types, C++20 ranges support).
+2. Reads from an iterator range, or an iterator and a sentinel of a different type (C++20 ranges support).
 
 The exact mapping and its limitations are described on a [dedicated page](../../features/binary_formats/ubjson.md).
 
@@ -43,7 +36,8 @@ The exact mapping and its limitations are described on a [dedicated page](../../
 :   a compatible iterator type
 
 `SentinelType`
-:   a sentinel type compatible with `IteratorType` (different from `IteratorType` and comparable via `operator!=`), for instance a custom sentinel type for C++20 ranges
+:   defaults to `IteratorType`; may be a different type comparable to `IteratorType` via `operator!=`, for instance a
+    custom sentinel type for C++20 ranges
 
 ## Parameters
 
@@ -114,7 +108,7 @@ Linear in the size of the input.
 - Added in version 3.1.0.
 - Added `allow_exceptions` parameter in version 3.2.0.
 - Extended container support (1) to include types with lvalue-only ADL `begin`/`end` (matching `std::begin`/`std::end` semantics) in version 3.13.0.
-- Added overload (3) for heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
+- Extended overload (2) to accept heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
 
 !!! warning "Deprecation"
 
diff --git a/docs/mkdocs/docs/api/basic_json/parse.md b/docs/mkdocs/docs/api/basic_json/parse.md
index 3af405cb1..4565c8762 100644
--- a/docs/mkdocs/docs/api/basic_json/parse.md
+++ b/docs/mkdocs/docs/api/basic_json/parse.md
@@ -10,15 +10,7 @@ static basic_json parse(InputType&& i,
                         const bool ignore_trailing_commas = false);
 
 // (2)
-template<typename IteratorType>
-static basic_json parse(IteratorType first, IteratorType last,
-                        const parser_callback_t cb = nullptr,
-                        const bool allow_exceptions = true,
-                        const bool ignore_comments = false,
-                        const bool ignore_trailing_commas = false);
-
-// (3)
-template<typename IteratorType, typename SentinelType>
+template<typename IteratorType, typename SentinelType = IteratorType>
 static basic_json parse(IteratorType first, SentinelType last,
                         const parser_callback_t cb = nullptr,
                         const bool allow_exceptions = true,
@@ -27,14 +19,11 @@ static basic_json parse(IteratorType first, SentinelType last,
 ```
 
 1. Deserialize from a compatible input.
-2. Deserialize from a pair of character iterators (same type)
+2. Deserialize from a pair of character iterators, or an iterator and a sentinel of a different type (C++20 ranges support)
     
     The `value_type` of the iterator must be an integral type with size of 1, 2, or 4 bytes, which will be interpreted
-    respectively as UTF-8, UTF-16, and UTF-32.
-3. Deserialize from an iterator and a sentinel (different types, C++20 ranges support)
-    
-    The `value_type` of the iterator must be an integral type with size of 1, 2, or 4 bytes, which will be interpreted
-    respectively as UTF-8, UTF-16, and UTF-32. The sentinel type must be comparable to the iterator type with `operator!=`.
+    respectively as UTF-8, UTF-16, and UTF-32. If `SentinelType` differs from `IteratorType`, it must be comparable to
+    the iterator type with `operator!=`.
 
 ## Template parameters
 
@@ -56,7 +45,7 @@ static basic_json parse(IteratorType first, SentinelType last,
     - a pair of pointers such as `ptr` and `ptr + len`
 
 `SentinelType`
-:   a sentinel type compatible with `IteratorType` (different from `IteratorType` and comparable via `operator!=`), for instance.
+:   defaults to `IteratorType`; may be a different type comparable to `IteratorType` via `operator!=`, for instance.
 
     - a custom sentinel type for C++20 ranges
     - `std::counted_iterator` with a different sentinel type
@@ -256,7 +245,7 @@ Invalid Unicode escapes and unpaired surrogates in the input are reported as
 - Changed [runtime assertion](../../features/assertions.md) in case of `FILE*` null pointers to exception in version 3.12.0.
 - Added `ignore_trailing_commas` in version 3.13.0.
 - Extended container support (1) to include types with lvalue-only ADL `begin`/`end` (matching `std::begin`/`std::end` semantics) in version 3.13.0.
-- Added overload (3) for heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
+- Extended overload (2) to accept heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
 
 !!! warning "Deprecation"
 
diff --git a/docs/mkdocs/docs/api/basic_json/sax_parse.md b/docs/mkdocs/docs/api/basic_json/sax_parse.md
index d7da30311..606ab9bbe 100644
--- a/docs/mkdocs/docs/api/basic_json/sax_parse.md
+++ b/docs/mkdocs/docs/api/basic_json/sax_parse.md
@@ -11,16 +11,7 @@ static bool sax_parse(InputType&& i,
                       const bool ignore_trailing_commas = false);
 
 // (2)
-template<class IteratorType, class SAX>
-static bool sax_parse(IteratorType first, IteratorType last,
-                      SAX* sax,
-                      input_format_t format = input_format_t::json,
-                      const bool strict = true,
-                      const bool ignore_comments = false,
-                      const bool ignore_trailing_commas = false);
-
-// (3)
-template<class IteratorType, class SentinelType, class SAX>
+template<class IteratorType, class SAX, class SentinelType = IteratorType>
 static bool sax_parse(IteratorType first, SentinelType last,
                       SAX* sax,
                       input_format_t format = input_format_t::json,
@@ -32,14 +23,11 @@ static bool sax_parse(IteratorType first, SentinelType last,
 Read from input and generate SAX events
 
 1. Read from a compatible input.
-2. Read from a pair of character iterators (same type)
+2. Read from a pair of character iterators, or an iterator and a sentinel of a different type (C++20 ranges support)
     
     The value_type of the iterator must be an integral type with a size of 1, 2, or 4 bytes, which will be interpreted
-    respectively as UTF-8, UTF-16, and UTF-32.
-3. Read from an iterator and a sentinel (different types, C++20 ranges support)
-    
-    The value_type of the iterator must be an integral type with a size of 1, 2, or 4 bytes, which will be interpreted
-    respectively as UTF-8, UTF-16, and UTF-32. The sentinel type must be comparable to the iterator type with `operator!=`.
+    respectively as UTF-8, UTF-16, and UTF-32. If `SentinelType` differs from `IteratorType`, it must be comparable to
+    the iterator type with `operator!=`.
 
 The SAX event lister must follow the interface of [`json_sax`](../json_sax/index.md).
 
@@ -56,11 +44,11 @@ The SAX event lister must follow the interface of [`json_sax`](../json_sax/index
       (as found via ADL or member functions, with semantics compatible to `std::begin` and `std::end`)
 
 `IteratorType`
-:   a compatible iterator type for overloads (2) and (3); a pair of character iterators whose `value_type` is an integral type
+:   a compatible iterator type for overload (2); a pair of character iterators whose `value_type` is an integral type
     with a size of 1, 2, or 4 bytes (interpreted respectively as UTF-8, UTF-16, and UTF-32)
 
 `SentinelType`
-:   a sentinel type compatible with `IteratorType` (different from `IteratorType` and comparable via `operator!=`) for overload (3)
+:   defaults to `IteratorType`; may be a different type comparable to `IteratorType` via `operator!=`, for overload (2)
 
 `SAX`
 :   a class fulfilling the SAX event listener interface; see [`json_sax`](../json_sax/index.md)
@@ -144,7 +132,7 @@ A UTF-8 byte order mark is silently ignored.
 - Ignoring comments via `ignore_comments` added in version 3.9.0.
 - Added `ignore_trailing_commas` in version 3.13.0.
 - Extended container support (1) to include types with lvalue-only ADL `begin`/`end` (matching `std::begin`/`std::end` semantics) in version 3.13.0.
-- Added overload (3) for heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
+- Extended overload (2) to accept heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
 
 !!! warning "Deprecation"
 
diff --git a/include/nlohmann/detail/input/input_adapters.hpp b/include/nlohmann/detail/input/input_adapters.hpp
index d646d228c..1ef8a6af7 100644
--- a/include/nlohmann/detail/input/input_adapters.hpp
+++ b/include/nlohmann/detail/input/input_adapters.hpp
@@ -491,10 +491,21 @@ struct can_compare_ne_reversed < IteratorType, SentinelType,
            : std::true_type {};
 
 template<typename IteratorType, typename SentinelType>
-struct can_compare_ne : std::integral_constant < bool,
+struct can_compare_ne_either_order : std::integral_constant < bool,
     can_compare_ne_impl<IteratorType, SentinelType>::value ||
     can_compare_ne_reversed<IteratorType, SentinelType>::value > {};
 
+// std::nullptr_t is excluded explicitly: a literal `nullptr` passed as a
+// trailing default argument (e.g. parse(s, nullptr, ...)) must never be
+// mistaken for a sentinel, and some compilers (e.g. GCC 4.8) unreliably
+// SFINAE the `operator!=` detection above for std::nullptr_t against
+// container/string types, which would otherwise make such calls ambiguous
+// with the compatible-input overload.
+template<typename IteratorType, typename SentinelType>
+struct can_compare_ne : std::integral_constant < bool,
+    !std::is_same<SentinelType, std::nullptr_t>::value &&
+    can_compare_ne_either_order<IteratorType, SentinelType>::value > {};
+
 template<typename T>
 struct is_iterator_of_multibyte
 {
@@ -520,19 +531,12 @@ struct iterator_input_adapter_factory<IteratorType, SentinelType, enable_if_t<is
     }
 };
 
-// General purpose iterator-based input (same-type iterators)
-template<typename IteratorType>
-typename iterator_input_adapter_factory<IteratorType, IteratorType>::adapter_type input_adapter(IteratorType first, IteratorType last)
-{
-    using factory_type = iterator_input_adapter_factory<IteratorType, IteratorType>;
-    return factory_type::create(first, last);
-}
-
-// General purpose iterator-based input (iterator+sentinel pair with different types)
-// Only enable for types that can be compared with !=
-template < typename IteratorType, typename SentinelType,
+// General purpose iterator-based input (iterator+sentinel pair; SentinelType
+// defaults to IteratorType for the common same-type case, but may differ for
+// C++20 ranges-style iterator+sentinel pairs). Only enable for types that can
+// be compared with !=.
+template < typename IteratorType, typename SentinelType = IteratorType,
            typename = typename std::enable_if <
-               !std::is_same<IteratorType, SentinelType>::value &&
                can_compare_ne<IteratorType, SentinelType>::value >::type >
 typename iterator_input_adapter_factory<IteratorType, SentinelType>::adapter_type input_adapter(IteratorType first, SentinelType last)
 {
diff --git a/include/nlohmann/json.hpp b/include/nlohmann/json.hpp
index 65ab0113a..a460bb29f 100644
--- a/include/nlohmann/json.hpp
+++ b/include/nlohmann/json.hpp
@@ -4083,34 +4083,17 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         return result;
     }
 
-    /// @brief deserialize from a pair of character iterators
+    /// @brief deserialize from a pair of character iterators (or an iterator+sentinel pair, C++20 ranges support)
     /// @sa https://json.nlohmann.me/api/basic_json/parse/
-    template<typename IteratorType>
-    JSON_HEDLEY_WARN_UNUSED_RESULT
-    static basic_json parse(IteratorType first,
-                            IteratorType last,
-                            parser_callback_t cb = nullptr,
-                            const bool allow_exceptions = true,
-                            const bool ignore_comments = false,
-                            const bool ignore_trailing_commas = false)
-    {
-        basic_json result;
-        parser(detail::input_adapter(std::move(first), std::move(last)), std::move(cb), allow_exceptions, ignore_comments, ignore_trailing_commas).parse(true, result); // cppcheck-suppress[accessMoved]
-        return result;
-    }
-
-    /// @brief deserialize from an iterator+sentinel pair (C++20 ranges support)
-    /// @sa https://json.nlohmann.me/api/basic_json/parse/
-    template<typename IteratorType, typename SentinelType>
+    template<typename IteratorType, typename SentinelType = IteratorType,
+             detail::enable_if_t<detail::can_compare_ne<IteratorType, SentinelType>::value, int> = 0>
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json parse(IteratorType first,
                             SentinelType last,
                             parser_callback_t cb = nullptr,
                             const bool allow_exceptions = true,
                             const bool ignore_comments = false,
-                            const bool ignore_trailing_commas = false,
-                            typename std::enable_if < !std::is_same<IteratorType, SentinelType>::value &&
-                                detail::can_compare_ne<IteratorType, SentinelType>::value >::type* = nullptr)
+                            const bool ignore_trailing_commas = false)
     {
         basic_json result;
         parser(detail::input_adapter(std::move(first), std::move(last)), std::move(cb), allow_exceptions, ignore_comments, ignore_trailing_commas).parse(true, result); // cppcheck-suppress[accessMoved]
@@ -4140,24 +4123,13 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         return parser(detail::input_adapter(std::forward<InputType>(i)), nullptr, false, ignore_comments, ignore_trailing_commas).accept(true);
     }
 
-    /// @brief check if the input is valid JSON
+    /// @brief check if the input is valid JSON (iterator pair, or iterator+sentinel pair for C++20 ranges support)
     /// @sa https://json.nlohmann.me/api/basic_json/accept/
-    template<typename IteratorType>
-    static bool accept(IteratorType first, IteratorType last,
-                       const bool ignore_comments = false,
-                       const bool ignore_trailing_commas = false)
-    {
-        return parser(detail::input_adapter(std::move(first), std::move(last)), nullptr, false, ignore_comments, ignore_trailing_commas).accept(true);
-    }
-
-    /// @brief check if the input is valid JSON (sentinel version)
-    /// @sa https://json.nlohmann.me/api/basic_json/accept/
-    template<typename IteratorType, typename SentinelType>
+    template<typename IteratorType, typename SentinelType = IteratorType,
+             detail::enable_if_t<detail::can_compare_ne<IteratorType, SentinelType>::value, int> = 0>
     static bool accept(IteratorType first, SentinelType last,
                        const bool ignore_comments = false,
-                       const bool ignore_trailing_commas = false,
-                       typename std::enable_if < !std::is_same<IteratorType, SentinelType>::value &&
-                           detail::can_compare_ne<IteratorType, SentinelType>::value >::type* = nullptr)
+                       const bool ignore_trailing_commas = false)
     {
         return parser(detail::input_adapter(std::move(first), std::move(last)), nullptr, false, ignore_comments, ignore_trailing_commas).accept(true);
     }
@@ -4187,33 +4159,16 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                : detail::binary_reader<basic_json, decltype(ia), SAX>(std::move(ia), format).sax_parse(format, sax, strict);
     }
 
-    /// @brief generate SAX events
+    /// @brief generate SAX events (iterator pair, or iterator+sentinel pair for C++20 ranges support)
     /// @sa https://json.nlohmann.me/api/basic_json/sax_parse/
-    template<class IteratorType, class SAX>
-    JSON_HEDLEY_NON_NULL(3)
-    static bool sax_parse(IteratorType first, IteratorType last, SAX* sax,
-                          input_format_t format = input_format_t::json,
-                          const bool strict = true,
-                          const bool ignore_comments = false,
-                          const bool ignore_trailing_commas = false)
-    {
-        auto ia = detail::input_adapter(std::move(first), std::move(last));
-        return format == input_format_t::json
-               ? parser(std::move(ia), nullptr, true, ignore_comments, ignore_trailing_commas).sax_parse(sax, strict)
-               : detail::binary_reader<basic_json, decltype(ia), SAX>(std::move(ia), format).sax_parse(format, sax, strict);
-    }
-
-    /// @brief generate SAX events (sentinel version)
-    /// @sa https://json.nlohmann.me/api/basic_json/sax_parse/
-    template<class IteratorType, class SentinelType, class SAX>
+    template<class IteratorType, class SAX, class SentinelType = IteratorType,
+             detail::enable_if_t<detail::can_compare_ne<IteratorType, SentinelType>::value, int> = 0>
     JSON_HEDLEY_NON_NULL(3)
     static bool sax_parse(IteratorType first, SentinelType last, SAX* sax,
                           input_format_t format = input_format_t::json,
                           const bool strict = true,
                           const bool ignore_comments = false,
-                          const bool ignore_trailing_commas = false,
-                          typename std::enable_if < !std::is_same<IteratorType, SentinelType>::value &&
-                              detail::can_compare_ne<IteratorType, SentinelType>::value >::type* = nullptr)
+                          const bool ignore_trailing_commas = false)
     {
         auto ia = detail::input_adapter(std::move(first), std::move(last));
         return format == input_format_t::json
@@ -4509,32 +4464,15 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         return res ? result : basic_json(value_t::discarded);
     }
 
-    /// @brief create a JSON value from an input in CBOR format
+    /// @brief create a JSON value from an input in CBOR format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
     /// @sa https://json.nlohmann.me/api/basic_json/from_cbor/
-    template<typename IteratorType>
-    JSON_HEDLEY_WARN_UNUSED_RESULT
-    static basic_json from_cbor(IteratorType first, IteratorType last,
-                                const bool strict = true,
-                                const bool allow_exceptions = true,
-                                const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error)
-    {
-        basic_json result;
-        auto ia = detail::input_adapter(std::move(first), std::move(last));
-        detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
-        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::cbor).sax_parse(input_format_t::cbor, &sdp, strict, tag_handler); // cppcheck-suppress[accessMoved]
-        return res ? result : basic_json(value_t::discarded);
-    }
-
-    /// @brief create a JSON value from an input in CBOR format (sentinel version)
-    /// @sa https://json.nlohmann.me/api/basic_json/from_cbor/
-    template<typename IteratorType, typename SentinelType>
+    template<typename IteratorType, typename SentinelType = IteratorType,
+             detail::enable_if_t<detail::can_compare_ne<IteratorType, SentinelType>::value, int> = 0>
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json from_cbor(IteratorType first, SentinelType last,
                                 const bool strict = true,
                                 const bool allow_exceptions = true,
-                                const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error,
-                                typename std::enable_if < !std::is_same<IteratorType, SentinelType>::value &&
-                                    detail::can_compare_ne<IteratorType, SentinelType>::value >::type* = nullptr)
+                                const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error)
     {
         basic_json result;
         auto ia = detail::input_adapter(std::move(first), std::move(last));
@@ -4584,30 +4522,14 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         return res ? result : basic_json(value_t::discarded);
     }
 
-    /// @brief create a JSON value from an input in MessagePack format
+    /// @brief create a JSON value from an input in MessagePack format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
     /// @sa https://json.nlohmann.me/api/basic_json/from_msgpack/
-    template<typename IteratorType>
-    JSON_HEDLEY_WARN_UNUSED_RESULT
-    static basic_json from_msgpack(IteratorType first, IteratorType last,
-                                   const bool strict = true,
-                                   const bool allow_exceptions = true)
-    {
-        basic_json result;
-        auto ia = detail::input_adapter(std::move(first), std::move(last));
-        detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
-        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::msgpack).sax_parse(input_format_t::msgpack, &sdp, strict); // cppcheck-suppress[accessMoved]
-        return res ? result : basic_json(value_t::discarded);
-    }
-
-    /// @brief create a JSON value from an input in MessagePack format (sentinel version)
-    /// @sa https://json.nlohmann.me/api/basic_json/from_msgpack/
-    template<typename IteratorType, typename SentinelType>
+    template<typename IteratorType, typename SentinelType = IteratorType,
+             detail::enable_if_t<detail::can_compare_ne<IteratorType, SentinelType>::value, int> = 0>
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json from_msgpack(IteratorType first, SentinelType last,
                                    const bool strict = true,
-                                   const bool allow_exceptions = true,
-                                   typename std::enable_if < !std::is_same<IteratorType, SentinelType>::value &&
-                                       detail::can_compare_ne<IteratorType, SentinelType>::value >::type* = nullptr)
+                                   const bool allow_exceptions = true)
     {
         basic_json result;
         auto ia = detail::input_adapter(std::move(first), std::move(last));
@@ -4655,30 +4577,14 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         return res ? result : basic_json(value_t::discarded);
     }
 
-    /// @brief create a JSON value from an input in UBJSON format
+    /// @brief create a JSON value from an input in UBJSON format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
     /// @sa https://json.nlohmann.me/api/basic_json/from_ubjson/
-    template<typename IteratorType>
-    JSON_HEDLEY_WARN_UNUSED_RESULT
-    static basic_json from_ubjson(IteratorType first, IteratorType last,
-                                  const bool strict = true,
-                                  const bool allow_exceptions = true)
-    {
-        basic_json result;
-        auto ia = detail::input_adapter(std::move(first), std::move(last));
-        detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
-        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::ubjson).sax_parse(input_format_t::ubjson, &sdp, strict); // cppcheck-suppress[accessMoved]
-        return res ? result : basic_json(value_t::discarded);
-    }
-
-    /// @brief create a JSON value from an input in UBJSON format (sentinel version)
-    /// @sa https://json.nlohmann.me/api/basic_json/from_ubjson/
-    template<typename IteratorType, typename SentinelType>
+    template<typename IteratorType, typename SentinelType = IteratorType,
+             detail::enable_if_t<detail::can_compare_ne<IteratorType, SentinelType>::value, int> = 0>
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json from_ubjson(IteratorType first, SentinelType last,
                                   const bool strict = true,
-                                  const bool allow_exceptions = true,
-                                  typename std::enable_if < !std::is_same<IteratorType, SentinelType>::value &&
-                                      detail::can_compare_ne<IteratorType, SentinelType>::value >::type* = nullptr)
+                                  const bool allow_exceptions = true)
     {
         basic_json result;
         auto ia = detail::input_adapter(std::move(first), std::move(last));
@@ -4726,30 +4632,14 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         return res ? result : basic_json(value_t::discarded);
     }
 
-    /// @brief create a JSON value from an input in BJData format
+    /// @brief create a JSON value from an input in BJData format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
     /// @sa https://json.nlohmann.me/api/basic_json/from_bjdata/
-    template<typename IteratorType>
-    JSON_HEDLEY_WARN_UNUSED_RESULT
-    static basic_json from_bjdata(IteratorType first, IteratorType last,
-                                  const bool strict = true,
-                                  const bool allow_exceptions = true)
-    {
-        basic_json result;
-        auto ia = detail::input_adapter(std::move(first), std::move(last));
-        detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
-        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::bjdata).sax_parse(input_format_t::bjdata, &sdp, strict); // cppcheck-suppress[accessMoved]
-        return res ? result : basic_json(value_t::discarded);
-    }
-
-    /// @brief create a JSON value from an input in BJData format (sentinel version)
-    /// @sa https://json.nlohmann.me/api/basic_json/from_bjdata/
-    template<typename IteratorType, typename SentinelType>
+    template<typename IteratorType, typename SentinelType = IteratorType,
+             detail::enable_if_t<detail::can_compare_ne<IteratorType, SentinelType>::value, int> = 0>
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json from_bjdata(IteratorType first, SentinelType last,
                                   const bool strict = true,
-                                  const bool allow_exceptions = true,
-                                  typename std::enable_if < !std::is_same<IteratorType, SentinelType>::value &&
-                                      detail::can_compare_ne<IteratorType, SentinelType>::value >::type* = nullptr)
+                                  const bool allow_exceptions = true)
     {
         basic_json result;
         auto ia = detail::input_adapter(std::move(first), std::move(last));
@@ -4773,30 +4663,14 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         return res ? result : basic_json(value_t::discarded);
     }
 
-    /// @brief create a JSON value from an input in BSON format
+    /// @brief create a JSON value from an input in BSON format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
     /// @sa https://json.nlohmann.me/api/basic_json/from_bson/
-    template<typename IteratorType>
-    JSON_HEDLEY_WARN_UNUSED_RESULT
-    static basic_json from_bson(IteratorType first, IteratorType last,
-                                const bool strict = true,
-                                const bool allow_exceptions = true)
-    {
-        basic_json result;
-        auto ia = detail::input_adapter(std::move(first), std::move(last));
-        detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
-        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::bson).sax_parse(input_format_t::bson, &sdp, strict); // cppcheck-suppress[accessMoved]
-        return res ? result : basic_json(value_t::discarded);
-    }
-
-    /// @brief create a JSON value from an input in BSON format (sentinel version)
-    /// @sa https://json.nlohmann.me/api/basic_json/from_bson/
-    template<typename IteratorType, typename SentinelType>
+    template<typename IteratorType, typename SentinelType = IteratorType,
+             detail::enable_if_t<detail::can_compare_ne<IteratorType, SentinelType>::value, int> = 0>
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json from_bson(IteratorType first, SentinelType last,
                                 const bool strict = true,
-                                const bool allow_exceptions = true,
-                                typename std::enable_if < !std::is_same<IteratorType, SentinelType>::value &&
-                                    detail::can_compare_ne<IteratorType, SentinelType>::value >::type* = nullptr)
+                                const bool allow_exceptions = true)
     {
         basic_json result;
         auto ia = detail::input_adapter(std::move(first), std::move(last));
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 06cda9a69..d910badb8 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -7328,10 +7328,21 @@ struct can_compare_ne_reversed < IteratorType, SentinelType,
            : std::true_type {};
 
 template<typename IteratorType, typename SentinelType>
-struct can_compare_ne : std::integral_constant < bool,
+struct can_compare_ne_either_order : std::integral_constant < bool,
     can_compare_ne_impl<IteratorType, SentinelType>::value ||
     can_compare_ne_reversed<IteratorType, SentinelType>::value > {};
 
+// std::nullptr_t is excluded explicitly: a literal `nullptr` passed as a
+// trailing default argument (e.g. parse(s, nullptr, ...)) must never be
+// mistaken for a sentinel, and some compilers (e.g. GCC 4.8) unreliably
+// SFINAE the `operator!=` detection above for std::nullptr_t against
+// container/string types, which would otherwise make such calls ambiguous
+// with the compatible-input overload.
+template<typename IteratorType, typename SentinelType>
+struct can_compare_ne : std::integral_constant < bool,
+    !std::is_same<SentinelType, std::nullptr_t>::value &&
+    can_compare_ne_either_order<IteratorType, SentinelType>::value > {};
+
 template<typename T>
 struct is_iterator_of_multibyte
 {
@@ -7357,19 +7368,12 @@ struct iterator_input_adapter_factory<IteratorType, SentinelType, enable_if_t<is
     }
 };
 
-// General purpose iterator-based input (same-type iterators)
-template<typename IteratorType>
-typename iterator_input_adapter_factory<IteratorType, IteratorType>::adapter_type input_adapter(IteratorType first, IteratorType last)
-{
-    using factory_type = iterator_input_adapter_factory<IteratorType, IteratorType>;
-    return factory_type::create(first, last);
-}
-
-// General purpose iterator-based input (iterator+sentinel pair with different types)
-// Only enable for types that can be compared with !=
-template < typename IteratorType, typename SentinelType,
+// General purpose iterator-based input (iterator+sentinel pair; SentinelType
+// defaults to IteratorType for the common same-type case, but may differ for
+// C++20 ranges-style iterator+sentinel pairs). Only enable for types that can
+// be compared with !=.
+template < typename IteratorType, typename SentinelType = IteratorType,
            typename = typename std::enable_if <
-               !std::is_same<IteratorType, SentinelType>::value &&
                can_compare_ne<IteratorType, SentinelType>::value >::type >
 typename iterator_input_adapter_factory<IteratorType, SentinelType>::adapter_type input_adapter(IteratorType first, SentinelType last)
 {
@@ -24976,34 +24980,17 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         return result;
     }
 
-    /// @brief deserialize from a pair of character iterators
+    /// @brief deserialize from a pair of character iterators (or an iterator+sentinel pair, C++20 ranges support)
     /// @sa https://json.nlohmann.me/api/basic_json/parse/
-    template<typename IteratorType>
-    JSON_HEDLEY_WARN_UNUSED_RESULT
-    static basic_json parse(IteratorType first,
-                            IteratorType last,
-                            parser_callback_t cb = nullptr,
-                            const bool allow_exceptions = true,
-                            const bool ignore_comments = false,
-                            const bool ignore_trailing_commas = false)
-    {
-        basic_json result;
-        parser(detail::input_adapter(std::move(first), std::move(last)), std::move(cb), allow_exceptions, ignore_comments, ignore_trailing_commas).parse(true, result); // cppcheck-suppress[accessMoved]
-        return result;
-    }
-
-    /// @brief deserialize from an iterator+sentinel pair (C++20 ranges support)
-    /// @sa https://json.nlohmann.me/api/basic_json/parse/
-    template<typename IteratorType, typename SentinelType>
+    template<typename IteratorType, typename SentinelType = IteratorType,
+             detail::enable_if_t<detail::can_compare_ne<IteratorType, SentinelType>::value, int> = 0>
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json parse(IteratorType first,
                             SentinelType last,
                             parser_callback_t cb = nullptr,
                             const bool allow_exceptions = true,
                             const bool ignore_comments = false,
-                            const bool ignore_trailing_commas = false,
-                            typename std::enable_if < !std::is_same<IteratorType, SentinelType>::value &&
-                                detail::can_compare_ne<IteratorType, SentinelType>::value >::type* = nullptr)
+                            const bool ignore_trailing_commas = false)
     {
         basic_json result;
         parser(detail::input_adapter(std::move(first), std::move(last)), std::move(cb), allow_exceptions, ignore_comments, ignore_trailing_commas).parse(true, result); // cppcheck-suppress[accessMoved]
@@ -25033,24 +25020,13 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         return parser(detail::input_adapter(std::forward<InputType>(i)), nullptr, false, ignore_comments, ignore_trailing_commas).accept(true);
     }
 
-    /// @brief check if the input is valid JSON
+    /// @brief check if the input is valid JSON (iterator pair, or iterator+sentinel pair for C++20 ranges support)
     /// @sa https://json.nlohmann.me/api/basic_json/accept/
-    template<typename IteratorType>
-    static bool accept(IteratorType first, IteratorType last,
-                       const bool ignore_comments = false,
-                       const bool ignore_trailing_commas = false)
-    {
-        return parser(detail::input_adapter(std::move(first), std::move(last)), nullptr, false, ignore_comments, ignore_trailing_commas).accept(true);
-    }
-
-    /// @brief check if the input is valid JSON (sentinel version)
-    /// @sa https://json.nlohmann.me/api/basic_json/accept/
-    template<typename IteratorType, typename SentinelType>
+    template<typename IteratorType, typename SentinelType = IteratorType,
+             detail::enable_if_t<detail::can_compare_ne<IteratorType, SentinelType>::value, int> = 0>
     static bool accept(IteratorType first, SentinelType last,
                        const bool ignore_comments = false,
-                       const bool ignore_trailing_commas = false,
-                       typename std::enable_if < !std::is_same<IteratorType, SentinelType>::value &&
-                           detail::can_compare_ne<IteratorType, SentinelType>::value >::type* = nullptr)
+                       const bool ignore_trailing_commas = false)
     {
         return parser(detail::input_adapter(std::move(first), std::move(last)), nullptr, false, ignore_comments, ignore_trailing_commas).accept(true);
     }
@@ -25080,33 +25056,16 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                : detail::binary_reader<basic_json, decltype(ia), SAX>(std::move(ia), format).sax_parse(format, sax, strict);
     }
 
-    /// @brief generate SAX events
+    /// @brief generate SAX events (iterator pair, or iterator+sentinel pair for C++20 ranges support)
     /// @sa https://json.nlohmann.me/api/basic_json/sax_parse/
-    template<class IteratorType, class SAX>
-    JSON_HEDLEY_NON_NULL(3)
-    static bool sax_parse(IteratorType first, IteratorType last, SAX* sax,
-                          input_format_t format = input_format_t::json,
-                          const bool strict = true,
-                          const bool ignore_comments = false,
-                          const bool ignore_trailing_commas = false)
-    {
-        auto ia = detail::input_adapter(std::move(first), std::move(last));
-        return format == input_format_t::json
-               ? parser(std::move(ia), nullptr, true, ignore_comments, ignore_trailing_commas).sax_parse(sax, strict)
-               : detail::binary_reader<basic_json, decltype(ia), SAX>(std::move(ia), format).sax_parse(format, sax, strict);
-    }
-
-    /// @brief generate SAX events (sentinel version)
-    /// @sa https://json.nlohmann.me/api/basic_json/sax_parse/
-    template<class IteratorType, class SentinelType, class SAX>
+    template<class IteratorType, class SAX, class SentinelType = IteratorType,
+             detail::enable_if_t<detail::can_compare_ne<IteratorType, SentinelType>::value, int> = 0>
     JSON_HEDLEY_NON_NULL(3)
     static bool sax_parse(IteratorType first, SentinelType last, SAX* sax,
                           input_format_t format = input_format_t::json,
                           const bool strict = true,
                           const bool ignore_comments = false,
-                          const bool ignore_trailing_commas = false,
-                          typename std::enable_if < !std::is_same<IteratorType, SentinelType>::value &&
-                              detail::can_compare_ne<IteratorType, SentinelType>::value >::type* = nullptr)
+                          const bool ignore_trailing_commas = false)
     {
         auto ia = detail::input_adapter(std::move(first), std::move(last));
         return format == input_format_t::json
@@ -25402,32 +25361,15 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         return res ? result : basic_json(value_t::discarded);
     }
 
-    /// @brief create a JSON value from an input in CBOR format
+    /// @brief create a JSON value from an input in CBOR format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
     /// @sa https://json.nlohmann.me/api/basic_json/from_cbor/
-    template<typename IteratorType>
-    JSON_HEDLEY_WARN_UNUSED_RESULT
-    static basic_json from_cbor(IteratorType first, IteratorType last,
-                                const bool strict = true,
-                                const bool allow_exceptions = true,
-                                const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error)
-    {
-        basic_json result;
-        auto ia = detail::input_adapter(std::move(first), std::move(last));
-        detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
-        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::cbor).sax_parse(input_format_t::cbor, &sdp, strict, tag_handler); // cppcheck-suppress[accessMoved]
-        return res ? result : basic_json(value_t::discarded);
-    }
-
-    /// @brief create a JSON value from an input in CBOR format (sentinel version)
-    /// @sa https://json.nlohmann.me/api/basic_json/from_cbor/
-    template<typename IteratorType, typename SentinelType>
+    template<typename IteratorType, typename SentinelType = IteratorType,
+             detail::enable_if_t<detail::can_compare_ne<IteratorType, SentinelType>::value, int> = 0>
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json from_cbor(IteratorType first, SentinelType last,
                                 const bool strict = true,
                                 const bool allow_exceptions = true,
-                                const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error,
-                                typename std::enable_if < !std::is_same<IteratorType, SentinelType>::value &&
-                                    detail::can_compare_ne<IteratorType, SentinelType>::value >::type* = nullptr)
+                                const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error)
     {
         basic_json result;
         auto ia = detail::input_adapter(std::move(first), std::move(last));
@@ -25477,30 +25419,14 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         return res ? result : basic_json(value_t::discarded);
     }
 
-    /// @brief create a JSON value from an input in MessagePack format
+    /// @brief create a JSON value from an input in MessagePack format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
     /// @sa https://json.nlohmann.me/api/basic_json/from_msgpack/
-    template<typename IteratorType>
-    JSON_HEDLEY_WARN_UNUSED_RESULT
-    static basic_json from_msgpack(IteratorType first, IteratorType last,
-                                   const bool strict = true,
-                                   const bool allow_exceptions = true)
-    {
-        basic_json result;
-        auto ia = detail::input_adapter(std::move(first), std::move(last));
-        detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
-        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::msgpack).sax_parse(input_format_t::msgpack, &sdp, strict); // cppcheck-suppress[accessMoved]
-        return res ? result : basic_json(value_t::discarded);
-    }
-
-    /// @brief create a JSON value from an input in MessagePack format (sentinel version)
-    /// @sa https://json.nlohmann.me/api/basic_json/from_msgpack/
-    template<typename IteratorType, typename SentinelType>
+    template<typename IteratorType, typename SentinelType = IteratorType,
+             detail::enable_if_t<detail::can_compare_ne<IteratorType, SentinelType>::value, int> = 0>
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json from_msgpack(IteratorType first, SentinelType last,
                                    const bool strict = true,
-                                   const bool allow_exceptions = true,
-                                   typename std::enable_if < !std::is_same<IteratorType, SentinelType>::value &&
-                                       detail::can_compare_ne<IteratorType, SentinelType>::value >::type* = nullptr)
+                                   const bool allow_exceptions = true)
     {
         basic_json result;
         auto ia = detail::input_adapter(std::move(first), std::move(last));
@@ -25548,30 +25474,14 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         return res ? result : basic_json(value_t::discarded);
     }
 
-    /// @brief create a JSON value from an input in UBJSON format
+    /// @brief create a JSON value from an input in UBJSON format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
     /// @sa https://json.nlohmann.me/api/basic_json/from_ubjson/
-    template<typename IteratorType>
-    JSON_HEDLEY_WARN_UNUSED_RESULT
-    static basic_json from_ubjson(IteratorType first, IteratorType last,
-                                  const bool strict = true,
-                                  const bool allow_exceptions = true)
-    {
-        basic_json result;
-        auto ia = detail::input_adapter(std::move(first), std::move(last));
-        detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
-        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::ubjson).sax_parse(input_format_t::ubjson, &sdp, strict); // cppcheck-suppress[accessMoved]
-        return res ? result : basic_json(value_t::discarded);
-    }
-
-    /// @brief create a JSON value from an input in UBJSON format (sentinel version)
-    /// @sa https://json.nlohmann.me/api/basic_json/from_ubjson/
-    template<typename IteratorType, typename SentinelType>
+    template<typename IteratorType, typename SentinelType = IteratorType,
+             detail::enable_if_t<detail::can_compare_ne<IteratorType, SentinelType>::value, int> = 0>
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json from_ubjson(IteratorType first, SentinelType last,
                                   const bool strict = true,
-                                  const bool allow_exceptions = true,
-                                  typename std::enable_if < !std::is_same<IteratorType, SentinelType>::value &&
-                                      detail::can_compare_ne<IteratorType, SentinelType>::value >::type* = nullptr)
+                                  const bool allow_exceptions = true)
     {
         basic_json result;
         auto ia = detail::input_adapter(std::move(first), std::move(last));
@@ -25619,30 +25529,14 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         return res ? result : basic_json(value_t::discarded);
     }
 
-    /// @brief create a JSON value from an input in BJData format
+    /// @brief create a JSON value from an input in BJData format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
     /// @sa https://json.nlohmann.me/api/basic_json/from_bjdata/
-    template<typename IteratorType>
-    JSON_HEDLEY_WARN_UNUSED_RESULT
-    static basic_json from_bjdata(IteratorType first, IteratorType last,
-                                  const bool strict = true,
-                                  const bool allow_exceptions = true)
-    {
-        basic_json result;
-        auto ia = detail::input_adapter(std::move(first), std::move(last));
-        detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
-        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::bjdata).sax_parse(input_format_t::bjdata, &sdp, strict); // cppcheck-suppress[accessMoved]
-        return res ? result : basic_json(value_t::discarded);
-    }
-
-    /// @brief create a JSON value from an input in BJData format (sentinel version)
-    /// @sa https://json.nlohmann.me/api/basic_json/from_bjdata/
-    template<typename IteratorType, typename SentinelType>
+    template<typename IteratorType, typename SentinelType = IteratorType,
+             detail::enable_if_t<detail::can_compare_ne<IteratorType, SentinelType>::value, int> = 0>
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json from_bjdata(IteratorType first, SentinelType last,
                                   const bool strict = true,
-                                  const bool allow_exceptions = true,
-                                  typename std::enable_if < !std::is_same<IteratorType, SentinelType>::value &&
-                                      detail::can_compare_ne<IteratorType, SentinelType>::value >::type* = nullptr)
+                                  const bool allow_exceptions = true)
     {
         basic_json result;
         auto ia = detail::input_adapter(std::move(first), std::move(last));
@@ -25666,30 +25560,14 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         return res ? result : basic_json(value_t::discarded);
     }
 
-    /// @brief create a JSON value from an input in BSON format
+    /// @brief create a JSON value from an input in BSON format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
     /// @sa https://json.nlohmann.me/api/basic_json/from_bson/
-    template<typename IteratorType>
-    JSON_HEDLEY_WARN_UNUSED_RESULT
-    static basic_json from_bson(IteratorType first, IteratorType last,
-                                const bool strict = true,
-                                const bool allow_exceptions = true)
-    {
-        basic_json result;
-        auto ia = detail::input_adapter(std::move(first), std::move(last));
-        detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
-        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::bson).sax_parse(input_format_t::bson, &sdp, strict); // cppcheck-suppress[accessMoved]
-        return res ? result : basic_json(value_t::discarded);
-    }
-
-    /// @brief create a JSON value from an input in BSON format (sentinel version)
-    /// @sa https://json.nlohmann.me/api/basic_json/from_bson/
-    template<typename IteratorType, typename SentinelType>
+    template<typename IteratorType, typename SentinelType = IteratorType,
+             detail::enable_if_t<detail::can_compare_ne<IteratorType, SentinelType>::value, int> = 0>
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json from_bson(IteratorType first, SentinelType last,
                                 const bool strict = true,
-                                const bool allow_exceptions = true,
-                                typename std::enable_if < !std::is_same<IteratorType, SentinelType>::value &&
-                                    detail::can_compare_ne<IteratorType, SentinelType>::value >::type* = nullptr)
+                                const bool allow_exceptions = true)
     {
         basic_json result;
         auto ia = detail::input_adapter(std::move(first), std::move(last));
diff --git a/tests/src/unit-bson.cpp b/tests/src/unit-bson.cpp
index 289f1f439..84b974b0f 100644
--- a/tests/src/unit-bson.cpp
+++ b/tests/src/unit-bson.cpp
@@ -1210,21 +1210,15 @@ TEST_CASE("BSON numerical data")
 
 TEST_CASE("Parse BSON directly from a file using iterator and sentinel")
 {
-    const json j = {{"key", "value"}, {"number", 42}};
-    std::vector<std::uint8_t> bson_bytes;
-    json::to_bson(j, bson_bytes);
+    std::string const filename = TEST_DATA_DIRECTORY "/json.org/1.json";
 
-    {
-        std::ofstream file("test_bson_sentinel.bson", std::ios::binary);
-        file.write(reinterpret_cast<const char*>(bson_bytes.data()), static_cast<std::streamsize>(bson_bytes.size()));
-    }
+    std::ifstream f_json(filename);
+    const json expected = json::parse(f_json);
 
-    std::ifstream file("test_bson_sentinel.bson", std::ios::binary);
+    std::ifstream file(filename + ".bson", std::ios::binary);
     std::istreambuf_iterator<char> first(file);
     const json parsed = json::from_bson(first, utils::istreambuf_sentinel{});
-    CHECK(parsed == j);
-
-    static_cast<void>(std::remove("test_bson_sentinel.bson"));
+    CHECK(parsed == expected);
 }
 
 TEST_CASE("BSON roundtrips" * doctest::skip())