libfyaml – fully-featured YAML 1.2 and JSON parser/writer

libfyaml is a fully-featured YAML 1.2 and JSON parser/writer with zero-copy operation and no artificial limits.

libfyaml is designed for high performance with zero content duplication, supporting arbitrarily large documents without the 1024-character limit on implicit keys found in other parsers. It passes the complete YAML test suite and provides both event-based (streaming) and document tree APIs for maximum flexibility.

This is free and open source software.

Key Features

• Zero-copy architecture – minimal memory usage, handles arbitrarily large documents.
• YAML 1.2 & JSON – full spec compliance, passes complete YAML test suite.
• Dual API – event-based streaming (like libyaml) or document tree manipulation.
• No artificial limits – unlike libyaml’s 1024-char implicit key restriction.
• High performance – up to 24x faster on large files with streaming mode, thread-safe lockless allocators.
• Rich manipulation – path expressions, scanf/printf-style APIs, programmatic document building.
• Production-ready – memory-safe, valgrind-clean, extensive test coverage.

Website: github.com/pantoniou/libfyaml
Support:
Developer: Pantelis Antoniou
License: MIT License

libfyaml is written in C. Learn C with our recommended free books and free tutorials.

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