Sandbox payloads beat another architecture slide
Architecture slides are useful for showing intent. They are poor at settling whether the order payload includes tax lines or whether the membership id is an integer forever. In API integration consulting we ask for a recorded sandbox payload early—ideally from the system that already produces it in a test environment.
One real payload collapses arguments that would otherwise consume a week of meetings. Optional fields become visible. Enums that only exist in someone’s head get written down. Auth headers that differ between environments stop being a surprise on cutover night.
If policy blocks sharing live-shaped data, invent a fixture that still matches the real schema and have both owners sign it. The fixture becomes the contract’s companion. Adapters are then judged against something concrete, not against a diagram with six coloured boxes.