Thymian

Thymian is an open-source HTTP conformance and API governance tool v0.1.8 (released April 2026, active development with frequent releases every 1-2 weeks). It validates APIs against RFC 9110 and OpenAPI specifications, offering static, live endpoint, and recorded traffic analysis. Key differentiators: language-agnostic, extensible via plugins (npm packages or WebSocket), educational reports explaining RFC semantics, and a unified rule system that works across lint, test, and analyze commands.