Why are both methods (PUT and PATCH) needed if PATCH can be used for full updates?

The PUT and PATCH methods serve different purposes, even though PATCH can be used for full updates.

• PUT is an idempotent method that replaces the entire resource. When you send a PUT request, you must provide a complete representation of the resource, and the server will replace the old resource with the new one.

• PATCH is intended for partial updates. You only send the fields you want to change, without needing to send the entire object.

Using both methods allows for clear operation boundaries: PUT for full updates, PATCH for partial updates. This improves API readability and optimizes traffic, as PATCH can transmit less data.

Example:

PUT /users/123
{
  "name": "Ivan",
  "email": "ivan@example.com"
}

PATCH /users/123
{
  "email": "new_email@example.com"
}

In the first case, the entire user is updated; in the second, only the email.