PUT is an HTTP method for creating a targeted resource when it does not exist or replacing it when it does. Its defining property is idempotence: repeating the same request should produce the same server outcome. section 5.5.1 section 1.1.4
Choose PUT only when repeated identical updates have the same effect. If every update deliberately changes server state—for example, refreshing a LastModifiedDate—use a nonidempotent method such as POST instead. section 5.5.1
Use the method whose semantics match the operation:
- Use PUT to replace a known resource or create it at the requested target when repetition remains idempotent. section 5.5.1
- Use POST to create a resource or perform a nonstandardized state change when repeated requests can produce different effects. section 5.5.1 section 1.1.4
- Distinguish PUT from PATCH: REST assigns PUT to replacement, while PATCH updates an existing resource. section 1.1.4
Board-game update decision
An API that updates a board game's name and year also records the current time in LastModifiedDate. Because each execution changes that timestamp, the operation is nonidempotent and is implemented with POST rather than PUT. section 5.5.1
