What is the difference between PATCH and PUT?

The main difference between PATCH and PUT lies in how they update resources:

• PUT is an operation that completely replaces a resource. When using PUT, the client sends a full representation of the resource, and the server replaces the existing resource with this new state. If some fields are not specified, they are usually considered deleted or reset.

• PATCH is a partial update operation. The client sends only the fields that need to be changed, and the server updates only those fields, leaving the others unchanged.

Example:

If you have a user object with fields name and email:

• PUT with body { "name": "Ivan", "email": "ivan@example.com" } will replace the entire object.
• PATCH with body { "email": "ivan_new@example.com" } will only change the email, leaving the name unchanged.

Thus, PATCH is more flexible for partial changes, while PUT is used for full resource replacement.