How can idempotency be verified?

Idempotency checks can be organized by using unique request or operation identifiers, which the server stores and checks upon re-execution.

For example:

• The client generates a unique key (e.g., UUID) for each operation.
• The server, upon receiving a request, checks whether a request with such a key has already been processed.
• If yes, the server returns the previous result without re-executing the operation.
• If no, it performs the operation and saves the result along with the key.

This prevents repeated changes to the state on repeated requests, ensuring idempotency at the business logic level.