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libyaml

The fast C library that forms the foundation of many YAML implementations.


Overview

libyaml is a YAML parser and emitter written in C. It's designed for speed and efficiency, and serves as the foundation for YAML libraries in many programming languages.


Why libyaml Matters

Foundation Layer

libyaml provides the parsing engine for:

  • pyyaml (Python) - Via C extension
  • Ruby YAML (Psych) - Ruby's standard YAML library
  • Perl YAML (YAML::XS) - High-performance Perl YAML
  • PHP yaml extension - PHP's native YAML support
  • Many other language bindings

Performance Critical

  • Written in C for maximum speed
  • Minimal memory footprint
  • Suitable for embedded systems
  • Optimized for high-throughput applications

YAML Specification Reference

  • Comprehensive YAML 1.1 implementation
  • Reference for implementers
  • Extensive test suite
  • Standards-compliant

The YAML Company Maintenance

Under The YAML Company's stewardship, libyaml receives:

Security First

  • Regular security audits
  • Memory safety improvements
  • Rapid vulnerability patching
  • Fuzzing and security testing
  • YES members get 48-hour early security notifications

Active Development

  • Bug fixes and stability improvements
  • Performance optimizations
  • YAML 1.2 specification support
  • Compiler and platform compatibility

Professional Support

  • Responsive to issues and pull requests
  • Clear development roadmap
  • Support for library consumers
  • Integration guidance

Maintenance & Accountability

libyaml is professionally maintained by The YAML Company, led by Ingy döt Net, co-creator of YAML.

  • Security contact: security@yaml.com
  • Disclosure policy: Coordinated disclosure with advance notice to YES members
  • Release cadence: Security patches prioritized, feature releases quarterly

Need supply chain documentation for compliance? Learn about the YES Program →


Language Bindings

libyaml has official and community bindings for:

Language Binding Status
Python pyyaml (C extension) Official
Ruby Psych Official
Perl YAML::XS Community
PHP yaml extension Community
Lua lua-yaml Community

Security

libyaml is regularly tested for security:

  • Continuous fuzzing with OSS-Fuzz
  • Static analysis
  • Memory safety testing (Valgrind, AddressSanitizer)
  • Security-focused code reviews

Recent security improvements:

  • Bounds checking
  • Integer overflow protection
  • Memory leak fixes
  • Stack limit enforcement

Support libyaml

libyaml is maintained through the YES Program. YES members get:

  • Priority support for libyaml issues
  • Early notification of security vulnerabilities
  • Influence over roadmap and feature development
  • Direct access to maintainers

Join the YES Program →


Resources