API Documentation Generator

API documentation generator for readable Markdown

The API documentation generator turns a structured list of REST endpoints into a ready-to-review Markdown document. Enter the interface name and version, an HTTP or HTTPS base URL, authorization mode, parameters, and an example JSON response. The result includes a table of contents, a section for each endpoint, parameter tables, and cURL commands without real credentials.

The tool is useful when starting an integration, organizing an existing API, or preparing concise documentation for a team or client. It does not attempt to replace a complete OpenAPI contract. Instead, it creates a predictable .md file that can be reviewed in a pull request, stored beside the code, and expanded with HTTP statuses, limits, data models, and versioning rules.

How to describe REST endpoints

Each endpoint occupies one row. A vertical bar separates three parts: method and path, a short description, and optional parameters. A parameter uses the format name:type:required, while commas separate multiple parameters. The value true marks a required field and false marks an optional one.

GET /users | List users | page:integer:false, limit:integer:false
POST /users | Create a user | name:string:true, email:string:true
GET /users/{id} | User details | id:integer:true

Method, path, and parameter validation

The generator accepts GET, POST, PUT, PATCH, DELETE, HEAD, and OPTIONS. A path must begin with a slash and cannot contain .., control characters, or fragments that could alter the generated Markdown or shell command. Parameter names begin with a letter or underscore. Supported types include string, integer, number, boolean, array, object, uuid, date, and datetime.

If a path contains {id}, the id parameter must appear in the list as required. Repeated names, an unknown type, or an invalid required flag stop generation and identify the affected row. An invalid endpoint is never skipped silently, so the output cannot look complete while part of the input has disappeared.

What the Markdown document contains

The response is parsed as JSON before being inserted and is rendered with readable indentation. A bad comma, an unclosed quote, or an excessively deep structure returns an error instead of producing a misleading example. If you are designing the data contract first, organize object constraints with the JSON Schema generator.

Authorization and safe cURL examples

Available modes are a Bearer token, an API key in the X-API-Key header, and no authorization. The generator never asks for a real token or key. Examples use the $TOKEN and $API_KEY variables, so a secret does not enter the result, tool history, or a file committed to a repository. The base URL is restricted to HTTP or HTTPS and cannot include embedded credentials.

What to add before publishing

The generated skeleton should be reviewed by the API owner. For every operation, add the meaning of 2xx, 4xx, and 5xx responses, the error shape, pagination rules, rate limits, and idempotency behavior. If the interface is consumed in a browser, prepare resource restrictions with the CSP header generator. The meta tags generator can help organize metadata for a public documentation page.

A practical documentation workflow

1. Select a preset or enter the API name, semantic version, and base address.
2. Add one row per endpoint, using stable names for types and parameters.
3. Paste fictional JSON that contains no personal data, access tokens, or secrets.
4. Select authorization, generate the document, and correct every reported input error.
5. Copy the Markdown into the repository, add the error contract, and verify examples in a test environment.

Update documentation in the same pull request as the endpoint implementation whenever possible. A reviewer can then compare the code and contract side by side. For an incompatible change, increment the major API version, document migration steps, and publish a retirement date for the previous version.

Frequently asked questions