ReadMe

GitBook

GitBook is a cloud‑based documentation platform that lets teams write, version, and publish product manuals, developer guides, and internal knowledge bases. Its editor supports markdown, rich text, and real‑time collaboration, making it easy to keep documentation up‑to‑date. Built for product and engineering teams, GitBook integrates with version‑control systems and communication tools, allowing seamless publishing to public sites or private workspaces. The platform offers a freemium tier with advanced features for growing organizations.

Mintlify

Mintlify is a documentation platform that helps teams build and maintain product and API documentation that stays current automatically. It positions itself as a knowledge layer for both human readers and AI agents, offering an API playground, authentication-aware docs, and an MCP server so AI tools can query documentation directly. The platform is used by companies ranging from large enterprises like Microsoft and Anthropic to YC-backed startups, and reports serving tens of millions of documentation page views. Paid tiers add unlimited editor seats, automation features, preview deployments, and enterprise controls like SSO, SCIM, and RBAC.

Swagger UI

Swagger UI provides a web-based interface that renders OpenAPI specifications as interactive documentation, allowing developers to explore and test endpoints directly in the browser. It supports live request execution, authentication flows, and dynamic request/response visualization. The project is open source, self‑hostable, and integrates seamlessly with existing API pipelines, making it ideal for both small services and large enterprise APIs.

Stoplight

Stoplight, now part of SmartBear, is an API design and documentation platform built around the OpenAPI specification. It gives teams a visual editor for designing APIs, generates interactive documentation automatically, and spins up local mock servers so front-end and back-end teams can work in parallel before an API is fully built. Stoplight promotes a design-first workflow with reusable models and components to keep specs DRY, and gives organizations visibility across their whole API portfolio. It also maintains open-source tooling, including the Spectral linter, the Prism mock server, and the Elements documentation component, and counts companies like Calendly, Schneider Electric, and PagerDuty among its customers.

Apidog

Apidog is an API development platform that combines design, debugging, automated testing, mocking, and documentation in a single tool, aiming to replace the combination of Postman, Swagger, and separate mocking tools that many teams stitch together. It supports a design-first workflow alongside request-based debugging, so teams can go from spec to working API and back. The platform includes real-time collaboration, interactive documentation publishing, and automated test suites that can run on a schedule. Pricing is per seat, with a free tier for small teams and paid Basic, Professional, and Enterprise tiers that add features like SSO, private mock clouds, and longer test report retention.