api-designer

Designing API contracts before implementation requires generating OpenAPI specifications and TypeScript types from architectural decisions. This approach ensures robust, well-documented interfaces that prevent misalignment between business requirements and actual code.

Contract-first API design is the process of defining OpenAPI specifications and interface types before any code is written. You need it to prevent misalignment between business requirements and implementation, ensuring clear API contracts guide downstream development.

Structuring a Next.js backend with three-tier architecture involves defining distinct route, service, and external layers. This separation generates clear architecture guidance and design plans, ensuring robust backend interfaces before implementation begins.

Generating OpenAPI specifications requires reading existing project documentation like systemArchitecture.md, openapi.yaml, techStack.md, glossary.md, and keyPairResponsibility.md. These files from the Documentation Hub provide the architectural context needed for accurate API design.

This contract-first API design process works best when planning interfaces before implementation. While it reads existing project documentation to generate OpenAPI outlines and TypeScript types, its core focus is delivering design plans for robust, well-documented new API contracts.

Contract-first API design produces OpenAPI outlines, TypeScript types, design plans, and implementation notes. These documentation-driven artifacts enable downstream developers to implement Next.js backends with precision based on predefined architectural decisions.