Can you explain what the term idempotency means in the context of programming and APIs?

Idempotence in programming and APIs means that performing the same operation with the same parameters multiple times will not change the system's state after the first call.

In simpler terms, if you call an idempotent method several times in a row, the result will be the same as if you called it once.

For example, the HTTP PUT method is usually idempotent: if you send a request to update a resource with the same data multiple times, the resource's state will not change after the first update.

This is important for system reliability to avoid unwanted side effects from repeated requests, such as due to network failures or resubmission of data.