Explain what idempotency means in the context of HTTP requests.

Idempotency in the context of HTTP requests means that performing the same request multiple times will result in the same outcome and server state as if the request was made once.

For example, the GET method is always idempotent — if you request the same resource multiple times, the data will not change. The PUT method is also idempotent, as updating a resource with the same data multiple times will not change the result.

In contrast, POST is usually not idempotent, as each request can create a new resource or change the server's state.

Idempotency is important for reliability and for executing requests repeatedly without side effects.