SimdJSON High-Speed Parser

This critically fast JSON parser exploits SIMD instructions (SSE4.2, AVX2, AVX-512, NEON, and SVE) to achieve parsing speeds of multiple gigabytes per second, making it the fastest JSON parser in the world. Developed by Daniel Lemire, John Keiser, and Geoff Langdale in 2019, the project has over 18,000 stars as of 2026 and is used by Microsoft, Intel, and numerous high-performance computing applications. Key features include: extreme performance (parsing JSON at over 3 GB/s on commodity hardware, 2-4x faster than RapidJSON and sajson, and 10x faster than standard library parsers on modern CPUs), SIMD-accelerated parsing (utilizing SSE4.2 and AVX2 on Intel, NEON on ARM, AVX-512 on modern processors, and SVE on ARM for wide vectorized character classification, structural character detection, and number parsing), on-demand parsing (lazy DOM parsing with iteratively navigable JSON structure, parsing only the parts of the document that are actually accessed, reducing memory and CPU usage for large documents), single-pass architecture (validating and parsing in a single pass without building intermediate representations), streaming API (parsing JSON documents larger than available memory via chunked input), minify API (in-place JSON whitespace removal via SIMD, over 10 GB/s minification speed), UTF-8 validation (fast UTF-8 validity checking using SIMD instructions), number parsing (exact parsing of IEEE 754 floating point numbers with correct rounding via the Eisel-Lemire algorithm), multi-document parsing (parsing multiple JSON documents from a single buffer with JSON and JSON Lines support), error handling (precise error reporting with byte offset and descriptive messages), and language bindings (C, C++, Rust, Python, Go, C#, Ruby, PHP, Java, Swift, and Node.js with native extension or FFI).