API-First Design Review Checklist
A design-review checklist for API-first development. It verifies the contract, naming, versioning, error format, security, and backward compatibility before implementation begins.
When to Use This Checklist
Use this checklist when adopting an API-first approach, where the contract is written and reviewed before any implementation. An API-first process treats the contract as the product: consumers and producers agree on it up front, then build in parallel against it. This review confirms the design is consistent, secure, and durable before code locks decisions in.
How to Use This Checklist
Start by writing the contract in OpenAPI for synchronous APIs or AsyncAPI for event-driven ones. Review naming, method semantics, and error formats against a style guide so the surface is predictable. Pin down versioning and deprecation policy early, because changing them later is expensive. Lint the contract in CI and generate mocks so consumers can integrate before the implementation exists.
The backward-compatibility review is mandatory whenever existing consumers depend on the API.
What Good Looks Like
A strong API-first design has a linted, versioned contract; consistent resource naming and HTTP semantics; standardized problem-details errors; and a clear deprecation policy. Authentication uses OAuth 2.0 / OIDC, writes support idempotency, and the contract is published for consumer review with generated mocks available. Backward compatibility with current consumers is verified.
Common Pitfalls
Teams write the contract after the code, which defeats the purpose and bakes in inconsistencies. Inconsistent error shapes force every consumer to special-case handling. Skipping a versioning policy makes the first breaking change a crisis. Not linting the contract lets drift between spec and implementation creep in.
Related Resources
See api-first design, OpenAPI specification best practices, and the Richardson maturity model for REST design. Problem details for HTTP APIs standardizes errors, and api-backward-compatibility guides safe evolution.