What is the fundamental difference between the GET and POST methods?

The GET method is used to retrieve data from the server. It is safe and idempotent, meaning it should not change the server's state, and repeated requests will not alter the result. Parameters are passed in the URL.

The POST method is intended for sending data to the server, for example, to create or modify resources. It is not idempotent and can change the server's state. Data is sent in the request body.

Key differences:

• GET is for retrieving data, POST is for sending data.
• GET parameters are in the URL, POST parameters are in the request body.
• GET requests can be cached, POST requests usually cannot.
• GET has length limitations on the URL, POST does not.

Example of GET:

GET /api/users?id=123 HTTP/1.1

Example of POST:

POST /api/users HTTP/1.1
Content-Type: application/json

{"name": "Ivan", "age": 30}