In a REST API, the payload refers to the data or information that is sent by the client in a request to the server or the data that is returned by the server. It is the essential information in the data block that you send or receive from the server. The payload can be sent or received in various formats such as JSON or XML. Accompanying the payload are HTTP headers which provide meta-information about the payload, such as its type (Content-Type header, e.g., application/json) and length (Content-Length header) . The payload is the body of the HTTP request and response message. The payload can be used in different HTTP methods such as POST, PUT, PATCH, and DELETE. In POST and PUT methods, the payload encompasses the complete data, while in PATCH, it contains only specific fields meant for modification. DELETE operations commonly dont have a payload, but some APIs expect additional deletion-related data in the request body.