Idempotency in Distributed Systems That Actually Works

Idempotency in distributed systems is the property that saves you after the network lies, the queue retries, the client panics, and the operator hits replay. In production systems, duplicate delivery is normal. Duplicate side effects are the bug. HTTP defines an idempotent method as one where multiple identical requests have the same intended effect on the server as one request. That is why PUT, DELETE, and safe methods are idempotent in protocol semantics and can be retried automatically after