What is the concept of idempotency in REST APIs and how is it implemented?

[fastqa]

Idempotency ensures that multiple identical requests have the same effect as a single request.

In REST APIs, GET, PUT and DELETE methods are idempotent, meaning if you call them multiple times, the result is the same as making a single call.

For instance, deleting a resource with DELETE is idempotent because, after the initial deletion, subsequent deletion requests have no object to act upon, so the state remains unchanged(resource remains deleted).

POST is not idempotent because sending the same request multiple times can create multiple new resources.