What is the primary function of the PATCH method?

The PATCH method is primarily used to apply partial modifications to a resource. Unlike the PUT method, which replaces the entire resource with a new representation, PATCH allows clients to send only the specific changes they want to make to a resource. This is particularly useful for scenarios where only a small part of the data needs to be updated, making PATCH efficient in terms of bandwidth and processing.

For instance, consider an API that manages user profiles. If you want to update only the user's email address rather than sending the entire profile data (which may include the name, age, address, etc.), you can use PATCH to specify just the email field that requires modification. This targeted approach reduces overhead and optimizes the interaction between client and server, making it a preferred method for making incremental updates to existing resources in RESTful APIs.