What is idempotency? How to achieve idempotency of a request in our case?

Idempotence is a property of an operation where performing the same request multiple times yields the same result as performing it once.

For example, if a request changes the state of a server, a repeated call should not lead to additional changes.

To achieve request idempotence, you can:

• Use unique identifiers (e.g., UUID) for operations and store them on the server so that repeated requests with the same ID are ignored or return the same result.
• Use HTTP methods that are inherently idempotent by standard (e.g., PUT, DELETE).
• In the request handling logic, check if the request has already been processed and do not perform the action again.

Example: when creating an order, the client generates a unique orderId and sends it with the request. The server checks if an order with this orderId already exists, and if so, returns the existing one without creating a new one.