POSTrequest

A POST request is an HTTP method used to submit data to a specified resource, often causing a change in server state such as creating a new resource or triggering a server-side process. The request includes a message body that carries the data to be processed by the target resource.

Unlike GET, which retrieves data, or PUT, which may be used to replace a resource at a known URL, POST does not define a direct resource URL for the outcome. POST is generally non-idempotent, meaning repeated identical requests may produce additional effects, such as creating multiple records.

A POST request line looks like: POST /path HTTP/1.1, accompanied by headers such as Content-Type and possibly Authorization. The body can be in various formats, with common types including application/json, application/x-www-form-urlencoded, and multipart/form-data for file uploads. The server may enforce size limits or streaming for large payloads.

Typical uses include submitting web forms, uploading files, or sending structured data to an API to create resources or trigger actions. The server's response often includes a status code indicating the result (for example, 201 Created for a new resource, 200 OK, 202 Accepted, or 204 No Content) and may include a body containing a representation or an identifier.

Security considerations include using HTTPS to protect the payload in transit, validating and sanitizing input to prevent injection, and implementing CSRF protection for web forms when cookies are used for authentication. When possible, be mindful of idempotence and design endpoints accordingly, recognizing that POST is intended for actions beyond simple retrieval.