The importance of API documentation for developers lies in its role as a comprehensive guide to using application programming interfaces (APIs). API documentation provides detailed information about the functionalities offered by an API, including methods, parameters, response structures, and examples. Good documentation helps developers understand how to integrate and utilize the API effectively, reducing the learning curve and minimizing errors during implementation. Furthermore, clear API documentation fosters collaboration among teams and enhances the overall developer experience, enabling faster development cycles and improved application performance by ensuring accurate integration with external services.