OpenAPI Directory is a comprehensive, community-maintained catalog of REST API definitions in OpenAPI 2.0 and 3.x formats.
The project addresses the fragmentation of API documentation across the web by collecting machine-readable API specifications in a single, searchable directory. It works by aggregating publicly available API definitions, converting non-OpenAPI formats into the OpenAPI 3.x standard, correcting errors found in approximately eighty percent of submitted definitions, and enriching entries with metadata like logos and categories. All definitions are automatically updated from their original sources at least weekly and validated before being committed to the repository. The directory is accessible both through browsing the repository and via a REST API, with RSS feeds available for newly added and recently updated APIs.
The tool suits developers and organizations that need to discover, reference, or integrate with public APIs without manually hunting through scattered documentation. It is particularly valuable for API tooling developers, API gateway operators, and teams building API clients or SDKs who want access to standardized, validated specifications. The project accepts contributions from anyone, not only API owners, making it a community-driven resource rather than a vendor-controlled listing. Adoption criteria for included APIs are strict: they must be publicly accessible, designed for long-term use rather than temporary events, and provide functionality beyond serving only their owner's needs.
The project maintains a weekly update cycle with automated validation against the official OpenAPI specification schemas. Community members actively contribute corrections and new API definitions, and the maintainers run systematic validation processes to catch specification compliance issues. The project provides a REST API for programmatic access to the entire collection, enabling integration into other tools and workflows.
