methodPOST

methodPOST is an HTTP method used to submit data to a specified resource, often causing a change in server state. It is defined in RFC 7231 and is commonly used to create resources or trigger server-side processing by sending data in the request body. Unlike safe methods such as GET, methodPOST is not safe and is not idempotent in general, meaning repeated identical requests may have additional effects or produce multiple resources.

In practice, methodPOST is commonly used to create a new resource under a collection URI (for example, POST /api/users to create a user) or to perform operations that do not fit neatly into resource retrieval. The server determines how to process the enclosed data, and responses typically include a status indicating the result. A 201 Created with a Location header is common when a new resource is created; a 200 OK may be returned with a response body; and a 202 Accepted can indicate that processing is asynchronous. A 204 No Content is possible when there is no response body.

Requests include a body with a Content-Type header that describes the data format, such as application/json, application/x-www-form-urlencoded, or multipart/form-data. Servers may apply authentication and authorization, input validation, and rate limiting. Clients should beware of the possibility of duplicate submissions and design accordingly; duplicates are a potential pitfall of methodPOST.

In RESTful APIs, methodPOST creates resources on a collection and contrasts with PUT (idempotent replacement) and PATCH (partial updates). Security considerations include CSRF protection and using TLS for transport. See also HTTP methods and HTTP status codes.