DELETE is idempotent as well.

GET and HEAD are not really "potent" as they don't cause state to change on the server (or at least shouldn't). So I usually prefer saying GET and HEAD are "safe".

The difference between safe and idempotent is:

- using an idempotent verb 0 or 1 times will have a different end state on the server.

- using a safe verb 0 or 1 times will have the same end state on the server.