Stoplight

ReadMe

ReadMe is a documentation platform built for teams that need to publish interactive, developer-facing API references and product docs. It generates interactive API explorers from OpenAPI specs, layers on a visual API Designer, and syncs bi-directionally with GitHub and GitLab so docs stay aligned with code changes. Beyond static reference pages, ReadMe adds real-time collaborative editing, branching and review workflows, reusable content blocks, and AI tools such as an AI Writer, a style linter, and an in-docs assistant. Enterprise customers get SSO, role-based access, audit logs, and SOC2/GDPR-aligned compliance features, and the platform is used by companies including NVIDIA, Amazon, and PagerDuty.

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.

Treblle

Treblle is a runtime intelligence platform for APIs that sits on top of existing infrastructure, capturing 100% of API traffic without sampling to give teams full observability, governance, and security visibility. It covers design-time and runtime rule enforcement, OWASP-based security checks, shadow endpoint detection, and per-request compliance audit trails. The platform is built for enterprise environments and deploys across SaaS, private cloud, air-gapped, and on-premise configurations, with the company stating it has processed over 500 billion API calls across customer environments. Its target users span CIOs tracking compliance ROI, enterprise architects governing multi-team APIs, product managers monitoring adoption, and InfoSec teams handling security review.

Mockoon

Mockoon is a desktop and CLI tool for creating and running mock REST APIs locally, without needing a remote server or an account. It offers an intuitive interface for designing realistic mock endpoints, with support for dynamic templating, rules-based response matching, JSON databases, proxy mode, and OpenAPI specification compatibility. The core desktop application and CLI are free and open source, while Mockoon Cloud adds paid capabilities like real-time team collaboration, cloud-hosted mock deployments, and automatic data synchronization. It is used by frontend and full-stack developers, QA teams, and API designers, including in regulated industries that value its offline-first, privacy-focused design.

Insomnia

Insomnia is a developer‑focused tool that lets you design, debug, and document APIs from a single, intuitive interface. It runs on Web, Windows, macOS, and Linux, providing a consistent experience wherever you work. With a freemium model, Insomnia offers robust features for individual developers and entire API teams, including collaboration, environment management, and seamless integration with popular API gateways and services.

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.