This guide offers an in-depth evaluation of the top API documentation tools of 2025, emphasizing the impact of AI advancements and heightened developer expectations on the industry. It covers tools ranging from Mintlify to GitBook, SwaggerHub, Docusaurus, Redocly, and Document360, helping teams choose based on features like interactivity, collaboration, and AI readiness. API documentation is crucial for developers, driving organic traffic and providing essential information for using and integrating APIs. Good documentation should be skimmable, well-written, and broadly helpful, with interactive features, AI-optimized formats, and interfaces tailored to developers' workflows. The article highlights examples like Stripe, Twilio, and Slack, which excel in creating developer-friendly documentation with features such as code snippets, interactive testing, and integrations with coding agents. API documentation tools are essential for managing the complexity of modern documentation needs, offering features like intuitive design, search functionality, collaboration, version control, and analytics. Mintlify is highlighted as a leading AI-native documentation tool, known for its developer experience, modern design, and integration of AI to enhance usability. As AI agents become significant API consumers, the demand for accurate, high-quality documentation is increasing, underscoring the importance of choosing the right tools to create and maintain effective API documentation.