Explain what idempotency means in the context of HTTP POST requests.

Idempotence in the context of HTTP means that making the same request to a resource with the same parameters multiple times will not change the server's state after the first request. For HTTP POST requests, idempotence is not guaranteed by default, as POST is typically used to create resources and can lead to different results upon repeated calls (for example, creating multiple records).

However, if POST is implemented so that repeated requests with the same data do not change the state (for example, updating a resource or ignoring duplicates), then it can be considered idempotent. Unlike POST, methods PUT, DELETE, and GET are supposed to be idempotent by standard.

Example: if a POST request creates a new order with a unique identifier, a repeated request will create a new order — not idempotent. If, however, POST updates the order status by ID, a repeated request will not change the result — idempotent.