What is the output format?

OpenAPI 3.0 YAML by default, with optional JSON export. The spec can be rendered by Swagger UI, Redoc, or any OpenAPI-compatible portal. Copy the YAML directly or download as a file.

Can I document WebSocket or gRPC APIs?

This tool is optimized for REST/HTTP APIs. For WebSocket use AsyncAPI format (not output here). For gRPC use the dedicated gRPC proto viewer tool.

Does it validate the spec it generates?

Yes — the generated YAML is validated against the OpenAPI 3.0 schema before export. Validation errors surface as inline warnings so you can fix them before sharing.

API Documentation Generator

DevTools Surf

Example: API Documentation Generator

A worked example, rendered from real sample data. Sign in to run the tool on your own input.

Input

User API
https://api.example.com/v1
GET /users

Output

# User API

**Base URL:** https://api.example.com/v1

## Endpoints

### GET /users

List all resources with pagination support.

#### Request
```
GET /users
```

#### Parameters
- `page` (query, int): Page number, default 1
- `limit` (query, int): Items per page, default 20

#### Headers
```
Authorization: Bearer <token>
Content-Type: application/json
```

#### Response (200 OK)
```json
{
  "data": [
    {"id": 1, "name": "Item 1"},
    {"id": 2, "name": "Item 2"}
  ],
  "meta": {"page": 1, "limit": 20, "total": 100}
}
```

#### Rate Limits
- 100 requests/minute for standard users
- Headers: X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset

About API Documentation Generator

API Documentation Generator preview - API / Config tool

Generate API documentation from request details. Part of the DevTools Surf developer suite. Browse more tools in the API / Config collection.

Use Cases

Create API docs for a new service before implementation (design-first)
Document third-party API integrations for team reference
Produce OpenAPI specs for import into Postman or Insomnia
Generate docs for legacy endpoints that have no existing specification

Tips

Fill in the endpoint path, HTTP method, and at least one request/response example — the generator infers schema from the example JSON
Add authentication details in the Security section; they appear as a 'requires auth' badge and code sample header
Use the 'Add endpoint' button to document multiple routes in one session and export them as a single OpenAPI file

Fun Facts

The original Swagger UI was released in 2011, making it one of the first interactive API documentation tools. It let developers call live APIs directly from the docs — a concept that changed API developer experience.
According to the 2023 State of the API report, REST APIs account for 86% of all API types in production, making REST documentation the highest-value format to generate.
Automatic documentation generation was popularized by Javadoc (1995) and Doxygen (1997) for code, but API-level documentation tools didn't become mainstream until the REST API boom of 2010-2015.

FAQ

What is the output format?: OpenAPI 3.0 YAML by default, with optional JSON export. The spec can be rendered by Swagger UI, Redoc, or any OpenAPI-compatible portal. Copy the YAML directly or download as a file.
Can I document WebSocket or gRPC APIs?: This tool is optimized for REST/HTTP APIs. For WebSocket use AsyncAPI format (not output here). For gRPC use the dedicated gRPC proto viewer tool.
Does it validate the spec it generates?: Yes — the generated YAML is validated against the OpenAPI 3.0 schema before export. Validation errors surface as inline warnings so you can fix them before sharing.

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