The purpose of API documentation for developers is to provide comprehensive guidelines and references regarding the functionality, usage, and integration of APIs. This documentation typically includes endpoint descriptions, request/response formats, and code examples, helping developers understand how to effectively utilize the API in their applications. Good documentation improves developer experience, reduces the learning curve, and accelerates the development process. By having clear and concise API documentation, developers can quickly implement and troubleshoot integrations, fostering better application performance.