Complete OpenAPI and Swagger toolchain online: editor, validator, preview, Postman conversion, cURL conversion, diff, lint, security, markdown docs, and code generation.
OpenAPI (formerly Swagger) is the industry-standard specification for describing RESTful APIs. An OpenAPI document — written in YAML or JSON, conforming to the OpenAPI Specification 3.0 or 3.1 — serves as the single source of truth for an API's structure: its paths, operations, parameters, request bodies, response schemas, authentication schemes, and server URLs. From this document, teams generate documentation, SDK clients, server stubs, mock servers, and automated tests. This hub provides the full OpenAPI toolchain.
The OpenAPI editor provides a live editing environment with syntax highlighting, real-time JSON Schema validation against the OpenAPI specification, and an integrated Swagger UI preview panel. API designers use it to iterate on a spec without switching between tools: a change to a schema definition immediately re-renders the interactive documentation, catching name mismatches and missing required fields as they type.
The OpenAPI validator performs a deep lint of a spec beyond basic schema validity: it checks that all $ref references resolve, that operationIds are unique, that security scheme references in operations match defined schemes in the components section, and that path parameters are defined in the parameters list. CI pipelines fail fast on these issues before they reach SDK generation.
The OpenAPI diff tool compares two versions of a spec and classifies changes as backward-compatible (adding optional fields, adding new endpoints) or breaking (removing fields, changing types, making previously optional parameters required). API platform teams use this to enforce versioning policies: any breaking change must bump the major API version.
The Postman-to-OpenAPI and OpenAPI-to-Postman converters bridge between the two formats, which have overlapping but distinct audiences. The curl-to-OpenAPI generator reverse-engineers a spec stub from example curl commands — a quick way to start documenting an undocumented API. The code generator produces client library stubs in multiple languages from a validated spec.