An API documentation generator creates professional reference pages for your REST endpoints. This tool builds OpenAPI 3.0 specs and downloadable HTML documentation — the same format used by Stripe, Twilio, and GitHub to document their APIs.
API Info
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API Documentation Preview
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How to Use the API Docs Generator
Professional API documentation is essential for developer adoption. Good docs answer three questions instantly: what endpoints exist, what parameters they accept, and what responses they return. This tool generates both human-readable HTML docs and machine-readable OpenAPI 3.0 JSON from your endpoint definitions.
Step 1: Fill in API Info
Start with the API title, version number, base URL (e.g., https://api.example.com/v1), and a short description. Select the authentication scheme your API uses — Bearer Token (for JWT), API Key, OAuth 2.0, or None. These fields populate the OpenAPI info and security definition sections.
Step 2: Load a Template or Add Endpoints
Click REST CRUD to load a complete set of Create/Read/Update/Delete endpoints for a User resource. Auth API loads register/login/logout/refresh endpoints. E-Commerce API loads products, cart, and orders. Or add individual endpoints: select an HTTP method, enter a path like /api/users/:id, and add a summary. Click the endpoint card to expand and add request parameters and response examples.
Step 3: Configure Endpoint Details
Click Edit endpoint on any endpoint card to expand its settings. Add request body fields with name, type (string/number/boolean/object/array), required flag, and description. Add response status codes (200, 201, 400, 401, 404, 500) with descriptions. Toggle the auth required flag to mark protected endpoints.
Step 4: Export Your Documentation
The preview panel renders a Swagger UI-style reference for all your endpoints, color-coded by HTTP method. Click Download HTML for a complete standalone documentation page, Download JSON for the OpenAPI 3.0 spec file (importable into Postman, Insomnia, Redoc, or Swagger UI), or Copy OpenAPI JSON to paste directly into your repository.
FAQ
Is the API docs generator free?
Yes, completely free. Build API documentation for any number of endpoints, use all templates, and export HTML or OpenAPI JSON without creating an account.
What is OpenAPI and why should I use it?
OpenAPI (formerly Swagger) is an industry-standard specification for describing REST APIs. An OpenAPI JSON file can be used to auto-generate client SDKs, import into tools like Postman or Insomnia, power interactive try-it documentation, and auto-generate server stubs.
Is the exported OpenAPI JSON compatible with Swagger UI?
Yes. The exported JSON follows OpenAPI 3.0 specification and is compatible with Swagger UI, Swagger Editor, Redoc, Stoplight, and any other tool that supports OpenAPI 3.0.
Is my API data private?
Yes. All API definition data stays in your browser. No endpoint definitions, parameters, or schema data is sent to any server. The HTML and JSON are generated entirely client-side.
Can I describe request and response bodies?
Yes. Each endpoint supports request body fields (name, type, required, description) and response fields (status code, description, example body). The OpenAPI export converts these into proper schema definitions.
What authentication schemes are supported?
The API info section supports None, Bearer Token (JWT), API Key (header), and OAuth2 authentication schemes. The selected scheme is reflected in the OpenAPI security definitions and displayed in the documentation preview.
How do I use the pre-built templates?
Click the REST CRUD, Auth API, or E-Commerce API template buttons to pre-populate the endpoint list with realistic sample endpoints. These serve as starting points you can modify, delete, or extend with your own endpoints.