An API request is a way for one software application to communicate with another. It allows developers to access specific features or data from a service, such as retrieving user information or sending messages. The request is typically made using a standard format, like HTTP, and includes details about what data is needed. When an API receives a request, it processes it and sends back a response. This response usually contains the requested data or a confirmation of an action taken. APIs are essential for building applications that rely on external services, enabling seamless integration and functionality.