openapi-spec-generator

Purpose

Extract and synthesize accurate, production-grade OpenAPI 3.1 / Swagger YAML specifications directly from route definitions, request/response models, validation schemas (Zod, Joi, Pydantic), and controller code.

When to Use

• Documenting REST APIs for external developer consumption.
• Generating interactive Swagger UI or Redoc documentation portals.
• Setting up automated SDK generation (via openapi-generator / stainless).

What to Analyze

1. Path & Operation Metadata: HTTP Method, summary, description, tags, and operationId.
2. Parameters: Path parameters ({id}), query parameters with types and defaults, and headers.
3. Request Body Schema: Content types (application/json), required fields, examples, and nested object types.
4. Response Status Codes: 200/201 Success payloads, 400 Bad Request validation schemas, 401/403 Auth errors, 404 Not Found.
5. Security Schemes: Bearer JWT (http), API Key (apiKey), or OAuth2 flows.

Output Format

• OpenAPI 3.1.0 YAML: Valid, lint-clean specification document.
• Reusable Component Schemas: components/schemas to eliminate JSON duplication.
• Swagger UI Integration Snippet: Fast setup instructions for documentation rendering.

Avoid

• Omitting error response definitions (400, 401, 404, 500).
• Hand-writing unstructured mock payloads without schema validation rules.