When to use Patch

(written by lawrence krubner, however indented passages are often quotes). You can contact lawrence at: lawrence@krubner.com

Interesting:

When should we use the PATCH HTTP method?

The HTTP methods PATCH can be used to update partial resources. For instance, when you only need to update one field of the resource, PUTting a complete resource representation might be cumbersome and utilizes more bandwidth

Also, the PUT method is idempotent. PUTting the same data multiple times to the same resource, should not result in different resources, while POSTing to the same resource can result in the creation of multiple resources.

See also
RFC 5789 – HTTP PATCH

Caveats

PATCH is neither safe nor idempotent.

An API implementing PATCH must patch atomically. It MUST not be possible that resources are half-patched when requested by a GET.

- See more at: http://restcookbook.com/HTTP%20Methods/patch/#sthash.kd69wThC.dpuf

Source