What is the difference between PUT and PATCH HTTP methods?

The PUT and PATCH HTTP methods are used to update resources on a server, but they differ in their approaches and use cases.

The PUT method is used to update a resource by replacing it with a new version. When a client sends a PUT request, it provides the complete representation of the resource. The server replaces the existing resource with the new one provided in the request. If the resource does not exist, the server may create it, depending on the implementation.

PUT is considered an idempotent operation, meaning that multiple identical PUT requests will produce the same result as a single request. This ensures consistency and predictability in updating resources. The client must send the entire resource representation, even if only a part of it has changed.

The PATCH method, on the other hand, is used to apply partial updates to a resource. When a client sends a PATCH request, it provides a set of changes or modifications to be applied to the resource. The server processes these changes and updates the resource accordingly, without replacing the entire resource.

PATCH is useful for scenarios where only a small portion of the resource needs to be updated, as it reduces the amount of data sent over the network. Unlike PUT, PATCH is not necessarily idempotent, meaning that multiple identical PATCH requests may produce different results depending on the state of the resource.

The main difference between PUT and PATCH lies in the nature of the update. PUT requires the complete resource representation and replaces the existing resource, while PATCH requires only the changes and applies them to the existing resource. This distinction affects how clients and servers handle updates and how they ensure consistency and efficiency.

In summary, the PUT HTTP method updates a resource by replacing it with a new one, requiring the complete representation of the resource. The PATCH HTTP method applies partial updates to a resource, requiring only the changes. PUT is idempotent, while PATCH may not be. The choice between PUT and PATCH depends on the specific requirements and the nature of the updates needed.