What is the difference between POST, PUT, and PATCH?

POST, PUT, and PATCH are HTTP methods used to send data to the server, but with different semantics:

• POST — creates a new resource. Usually used for adding new data. Each POST call can create a unique new resource.

• PUT — completely replaces an existing resource or creates it if it does not exist. Idempotent, meaning repeated requests with the same data will not change the result.

• PATCH — partially updates a resource. Used when only some fields need to be changed, not the entire object.

Example:

POST /users
{
  "name": "Ivan",
  "age": 30
}

PUT /users/123
{
  "name": "Ivan",
  "age": 31
}

PATCH /users/123
{
  "age": 31
}

Here, POST creates a new user, PUT completely replaces the user with id 123, and PATCH only changes the age of the user with id 123.