−A customer can deliberately order the same item and quantity twice. If the server merges orders solely because their request bodies have the same hash, it loses that intention. Here the caller supplies an identifier: it reuses the key for the same operation and chooses a new one for a separate order. The server defines the caller and key scope, how it handles different content under one key, and how long it retains the record. AWS article.
+A customer may intentionally order the same item and quantity twice, so hashing the request body alone would collapse two legitimate orders into one. Instead, the caller supplies an explicit request key—reusing it when retrying the same operation and generating a new key for a separate order. The server scopes each key to the authenticated caller, rejects payload mismatches under the same key, and defines the retention window for stored records. AWS article.
