A client sends a request to create an order. The server processes it, but the connection drops before the response reaches the client. The client retries. How can the API recognise that retry and avoid creating another order? This is the problem my open-source Spring Boot Idempotency Starter aims to address. What is idempotency? For an API operation, idempotency means that repeating the same logical request should not produce additional side effects. An idempotency key...