Fern generates interactive API Reference documentation from an OpenAPI specification or other API formats. Endpoints, type schemas, code snippets, and AI-generated examples are all populated automatically. Users can try requests directly from the docs with the API Explorer, and AI agents and crawlers can discover your APIs via the API catalog endpoint.
OpenAPI specification
Protocol Buffer .proto files
AsyncAPI specification
OpenAPI specification
OpenRPC specification
GraphQL schema
Python or C++ source code