API-First OpenAPI Design & Codegen Workflow
AI-generated workflow example for an OpenAPI draft, type generation, handlers and integration tests. Check generated schemas and commands against your project.
Tags: workflow, api-first, openapi, swagger, zod, codegen, rest
Category: coding
Listing attribution: SimplyUtils
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API-First OpenAPI Design & Codegen Workflow
Workflow Overview
An API-First Development Workflow ensures that backend endpoints and client API callers remain 100% in sync without schema drift.
Multi-Phase Steps
Phase 1: OpenAPI 3.1 Specification
Draft the contract in docs/openapi.yaml specifying paths, parameters, schemas, and error responses.
Phase 2: Schema Codegen
Execute schema generation tools to convert OpenAPI specifications to Zod or TypeScript types:
npx openapi-typescript docs/openapi.yaml -o shared/api-types.tsPhase 3: Express / Route Implementation
Implement handlers using the generated Zod validation middleware:
import { createResourceSchema } from "shared/api-types";
app.post("/api/resources", validateBody(createResourceSchema), async (req, res) => {
// Strongly typed handler
});Phase 4: Verification & Automated Integration Test
Run Supertest or Vitest API suite to confirm responses match the OpenAPI contract.