What information is typically provided in an API documentation?

API documentation is primarily designed to guide developers on how to effectively use an application programming interface (API). It typically includes comprehensive information such as endpoints, methods, parameters, and response formats, which are essential for developers to understand how to interact with the API. Additionally, it may contain examples of how to make requests, handle responses, and error messages, all of which are crucial for implementing the API in applications correctly.

While other options may provide useful information in different contexts, they are not the focus of API documentation. Gaining an understanding of the entire programming language is broader than what one would find in API documentation. Performance metrics are usually outside the scope of API documentation, which does not generally deal with the performance of the overall application. Lastly, details about user interface design typically pertain to front-end development rather than the technical specifications and functionalities provided by an API.