API Design Reviews

Before implementing an endpoint, it helps to work through what its response will mean to a client. Consider a proposed order-cancellation endpoint that accepts an order ID and returns success: true. The route looks reasonable, the JSON is valid, and the implementation seems small. But several decisions remain unresolved: whether cancellation has finished, what happens if shipping starts at the same time, and whether a retry creates another cancellation attempt.

An API design review examines those decisions before clients depend on them.

This chapter explains how to prepare a reviewable proposal, investigate important scenarios, write actionable findings, and close the review after checking that the agreed contract clearly states what to implement and how to verify it.