What is the main purpose of the POST HTTP method?

The main purpose of the POST HTTP method is to create a resource or post data to the server. When a client sends a POST request, it typically includes data in the request body, which can be used by the server to create a new resource. This could involve submitting form data, uploading files, or sending other types of data that the server will process.

Using POST is essential when the client wants to send substantial data to the server that does not fit within the URL’s length limits or when the operation is not idempotent—meaning that sending the same POST request multiple times may result in different states on the server. Unlike the GET method, which is used to retrieve data, POST is specifically designated for actions that involve sending data to the server to affect its state or create new resources.

While other HTTP methods like PUT and DELETE have their specific purposes for updating and removing resources respectively, POST's role focuses primarily on creation, making it a fundamental part of RESTful API design and interaction.