What are the differences between the HTTP methods GET, POST, and PUT in terms of their usage and behavior?

Main differences between HTTP methods GET, POST, and PUT:

• GET is used to retrieve data from the server. GET requests should not change the server's state and are usually cached. Parameters are passed in the URL.

• POST is used to create new resources or send data to the server. POST requests can change the server's state and are not cached. Data is sent in the request body.

• PUT is used to update an existing resource or create a resource at a specified URI. PUT requests are idempotent — repeating the same request with the same data will not change the result.

Example:

// GET request to retrieve a user
GET /users/123

// POST request to create a user
POST /users
{
  "name": "Ivan",
  "age": 30
}

// PUT request to update a user
PUT /users/123
{
  "name": "Ivan Ivanov",
  "age": 31
}