Understanding safe, idempotent, and unsafe HTTP methods in the context of carrier APIs.
Safe methods (GET, HEAD, OPTIONS) don't modify state. Idempotent methods (GET, PUT, DELETE) produce the same result when called multiple times. POST and PATCH are neither safe nor idempotent.
For carrier APIs:
- GET: fetch shipment status, tracking info
- POST: create shipments (use idempotency keys)
- PUT: update shipment details (naturally idempotent)
- DELETE: cancel/void shipments