Multi Step Processes easy
A client app sends a 'Pay $50' request to your API. The server processes the payment but the network response is lost. The client automatically retries the request. What prevents the user from being charged $100?
- A The load balancer detects duplicate IP addresses.
- B The server checks for an Idempotency Key sent by the client.
- C SSL encryption prevents replay attacks.
- D The database uses a sequential primary key.
Answer: B. The server checks for an Idempotency Key sent by the client.
An Idempotency Key is a unique ID generated by the client for a specific action. If the server sees the same key twice, it knows it is a retry of the same operation and returns the previous result instead of executing it again.
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