The Best API Documentation Tool

# Redocly > OpenAPI-generated documentation tool with 24k+ stars on Github - make APIs your company's superpower. ## Table of contents - [API-first design](https://redocly.com/blog/api-first.md) - [Why API catalogs are critical for agentic software development | Redocly](https://redocly.com/blog/api-catalogs-agentic-software.md): Learn how API catalogs transform from static documentation into active systems of record for AI agents, enabling safe discovery and execution of tools in software development workflows. - [What you really need to build an API sandbox | Redocly](https://redocly.com/blog/api-sandbox-requirements.md): Discover the critical requirements for building API sandboxes that support complex workflows, from environmental isolation to webhook simulation and deterministic testing. - [Hello world, our mission is to perfect the API Developer Portal](https://redocly.com/blog/api-dev-portal.md): ReDoc was born out of frustration with rendering my OpenAPI definitions for API reference docs. - [How to reuse schemas when required properties change across endpoints](https://redocly.com/blog/all-of-schemas.md): Answering real questions about how to use OpenAPI to design and describe APIs. - [API catalog as the AI substrate of the future | Redocly](https://redocly.com/blog/api-catalog-ai-substrate.md): Discover how API catalogs become essential infrastructure when AI agents work alongside developers. Learn why catalogs must extend beyond APIs to include services, people, and AI agents. - [The unseen economics of an API catalog | Redocly](https://redocly.com/blog/api-catalog-value.md): Discover how API catalogs deliver millions in ROI by eliminating search waste, preventing costly mistakes, and enabling faster development through automation and trust. - [API into AI](https://redocly.com/blog/api-into-ai.md): Smooth management transition and new product announcement. - [Add OpenAPI tags for next-level API descriptions](https://redocly.com/blog/add-openap