To ensure that a customer order is only processed once, which of the following should you do?

Using the Idempotency-Key header to the order ID is an effective way to ensure that a customer order is only processed once. When you set an Idempotency-Key for a transaction, it signals to the Stripe API that you want to treat the request as a unique operation. If the same request is sent multiple times, such as in cases of network retries or user error, Stripe will recognize the Idempotency-Key and not process the transaction again if it has already been executed. This prevents duplicate transactions and ensures that the order is processed only once.

While using a unique order ID for each transaction is important for tracking and organization, it does not inherently prevent the same order from being processed multiple times. Confirming the order with the customer does ensure that they intended to make the purchase, but doesn’t safeguard against processing errors. Processing transactions in a batch can be efficient, but it doesn’t inherently manage the risk of duplicates unless accompanied by additional safeguards. Therefore, utilizing the Idempotency-Key is a robust solution specifically designed to handle this issue effectively.