Have you encountered the concept of idempotency? How did you implement it?

Idempotency is a property of an operation where multiple executions with the same input do not change the result after the first application.

In systems, this is important for ensuring reliability during repeated requests, for example, due to network failures or timeouts.

Implementing idempotency often involves:

• Using unique request identifiers (idempotency keys).
• Storing the state of completed operations and returning the same result for repeated requests with the same key.

Example: when paying for an order, a client may resend the request due to a network error. The server checks the idempotency key, and if an operation with such a key has already been completed, it returns the previous result without creating duplicate transactions.

This reduces the risk of errors and increases the system's resilience to failures.