Best 6 OpenAPI Documentation Tools to use in 2025

Fern is a platform that automatically generates SDKs and API documentation from your API definition. You provide your OpenAPI, AsyncAPI, or gRPC specification, and Fern creates ready-to-use client libraries in languages like TypeScript, Python, Go, Java, Ruby, C#, PHP, and Swift.

Speakeasy is a complete API toolchain that transforms your OpenAPI specification into ready-to-use developer tools. It creates native SDKs that follow best practices for each programming language, making them feel handwritten rather than machine-generated.

API Hub is an all-in-one platform for the complete API development process. It lets you design APIs using a visual editor or code, test them automatically, create documentation, and share with users through branded portals.

Redocly is an API documentation platform that helps you build professional developer portals. You start with an OpenAPI file that describes your API, and Redocly transforms it into clean, readable documentation with examples and interactive features.

Stoplight is a web-based platform for API design and management that follows a design-first philosophy. This means you plan and design your API before writing any code, which saves time and reduces errors during development.

Scalar is a platform for building API documentation that looks professional and works smoothly. You provide your OpenAPI document, and Scalar transforms it into easy-to-read pages with examples and testing tools built in.