Major Features

• RFC compliance for JSON Patch and JSON Merge Patch
• Big endian architecture support
• std::chrono JSON support
• Enhanced BEVE format streaming capabilities

Big Endian Support

Full support for big endian architectures with compile-time detection via std::endian::native. Includes byte-swapping implementations across all components, with CI testing through GCC cross-compilation and QEMU. (Closes [#1675])

• [#2141]

JSON Patch (RFC 6902)

Complete implementation of RFC 6902 JSON Patch for computing and applying document differences:

• glz::diff() - Generate patches between documents
• glz::patch() - Apply operations in-place
• glz::patched() - Non-mutating patch application
• glz::patch_json() - Work directly with JSON strings
• All six operations: add, remove, replace, move, copy, test
• Atomic transactions with automatic rollback on failure
• Option to create missing intermediate paths
• [#2131]

JSON Merge Patch (RFC 7386)

Full support for RFC 7386 JSON Merge Patch:

• merge_patch() - Apply patches in-place
• merge_patched() - Returns new patched value
• merge_diff() - Generate patches between documents
• Correct handling of null-value removal, recursive merging, and array replacement
• [#2132]

std::chrono Support

Zero-allocation serialization for chrono types: (Closes [#1110])

• std::chrono::duration - Serialized as numeric count
• std::chrono::system_clock::time_point - ISO 8601 UTC format
• std::chrono::steady_clock::time_point - Numeric format
• Epoch wrappers: epoch_seconds, epoch_millis, epoch_micros, epoch_nanos
• Precision-aware fractional seconds based on duration type
• Automatic timezone offset conversion to UTC
• [#2130]

BEVE Delimiter and Incremental Writing

New streaming capabilities for BEVE (Binary Efficient Value Encoding) similar to NDJSON for JSON:

• write_beve_delimiter() - Outputs delimiter byte (0x06)
• write_beve_append() - Adds values without clearing buffer
• write_beve_append_with_delimiter() - Streaming-friendly writes
• write_beve_delimited() - Container serialization with delimiters
• read_beve_delimited() - Read delimiter-separated values
• read_beve_at() - Offset-based reading with automatic delimiter skipping

When converting delimited BEVE to JSON via beve_to_json, delimiters become newlines for NDJSON-compatible output.

• [#2142]

std::u8string and std::u8string_view Support

Native serialization support for UTF-8 string types.

• [#2127]

mimic Type in glz::meta

New mimic type alias to prevent double-quoting of custom types as map keys: (Closes [#1477])

:::cpp
template <>
struct glz::meta<my_key> {
   using mimic = std::string;
   static constexpr auto value = &my_key::value;
};

• [#2123]

Networking Improvements

• HTTP Server Keep Alive - Persistent connection support for HTTP servers [#2128]
• WebSocket internal() Methods - Access underlying implementation via internal() and socket() methods [#2140]

Performance Improvements

• Reduced template instantiations when various glz::opts are used, decreasing compile times [#2138]
• Pass end iterator by value for higher performance in parsing [#2133]
• Pass std::string_view by value throughout codebase [#2134]
• Remove reinterpret_cast from atoi implementation [#2136]

Code Cleanup

• Removed legacy hash_map implementation and cleaned up variant hashing [#2135]

Bug Fixes

• Fixed glz::seek for invalid paths to maps by using find [#2129]

Breaking Changes

• Error code renamed: get_nonexistent_json_ptr → nonexistent_json_ptr for consistency [#2131]

Full Changelog: https://github.com/stephenberry/glaze/compare/v6.2.0...v6.3.0