UseFreeTools

API Documentation Writer

Draft API explanations around supplied routes or bounded OpenAPI JSON without making API calls.

No sign-up Free to use

Your input

Combined text limit: 12,000 characters.

Your input is sent to the site's configured AI providers. If one cannot complete the request, another may receive it. Private files and results expire within one hour. Review the result before using it. Privacy details.

Fill in the fields, then submit when you are ready.

Result

Your result will appear here after you submit and complete verification.

How to use API Documentation Writer

  1. Choose Routes CSV or OpenAPI 3 JSON and paste the matching source. Routes CSV needs the exact header id,method,path,description and 1 to 12 operations.
  2. For CSV, use a unique ID, a supported uppercase HTTP method, a path starting with one slash and a nonblank description. For OpenAPI, each operation needs a description or summary; use a small JSON excerpt rather than YAML.
  3. Add Reader context if the explanations need a particular level of detail. Remove credentials and private source details before submitting to the configured AI service.
  4. Select Draft API documentation and complete browser verification when prompted. Compare generated summaries and explanations with the attached source methods, paths, descriptions and metadata.
  5. Review Open questions and unresolved local references in the original specification. The tool neither calls the endpoints nor verifies that supplied examples match a running service.

Example: API Documentation Writer

Explain supplied endpoint definitions without inventing routes.

You add
Specification format: Routes CSV Supplied routes or specification: id,method,path,description R1,GET,/items,List the available items. R2,GET,/items/{id},Return one item by its supplied ID. Reader context: Developers reading a draft of the supplied route descriptions.
You get
Every accepted operation keeps its source method and path. Explanations quote its description; OpenAPI parameters, response codes and inline examples come from supplied JSON.

Options

Route CSV
Use the exact header id,method,path,description. Each operation needs a unique ID and a path beginning with a slash.
OpenAPI JSON
Use a bounded OpenAPI 3.x JSON excerpt. Local references remain inert text. Remote references, YAML input and external example retrieval are unsupported.

Supported inputs and limits

  • The supplied specification allows 8,000 characters and 1 to 12 operations;
  • Reader context allows 500.
  • CSV methods are GET, POST, PUT, PATCH, DELETE, HEAD and OPTIONS.
  • Paths start with one slash, not a URL, and allow 200 characters without whitespace.
  • Each operation description or OpenAPI summary allows 1,000 characters.
More details

OpenAPI input is a bounded 3.x JSON object with paths, a maximum nesting depth of 32 and unique object member names.

Parsed metadata must fit within 20,000 UTF-8 bytes.

Inline examples allow three distinct values per operation, 1,024 bytes per value and 8,000 bytes across the excerpt.

Numeric values that would lose precision are refused.

Local references beginning with # stay unresolved.

Remote references, YAML, external example retrieval, API calls and code execution are unsupported.

Generated explanations can still misinterpret genuine source excerpts; this is a documentation draft rather than full OpenAPI validation or an observed service test.

Where your input is processed

Your input is uploaded to this site and sent to a configured AI provider. If a provider fails, the request may be sent to the next eligible provider. Check its result before use. Private inputs and results expire within one hour and are excluded from site backups; temporary files are removed by scheduled cleanup. Provider retention rules may differ. Avoid submitting passwords or highly sensitive information.

Keep source definitions beside generated explanations

Start by checking the method, path and parameters, then review how the prose explains them. A genuine source quote can still be interpreted incorrectly. Supplied response codes and examples describe the specification rather than observed API behavior. Compare the draft with actual service documentation and your own tests before publishing it, especially where authentication, errors or optional fields affect client behavior.

Questions about API Documentation Writer

Does it call the endpoints?

No requests are sent to documented paths. The site cannot confirm availability, authentication requirements or actual response behavior.

Where do code examples come from?

Only supplied inline OpenAPI example values are shown as source JSON. Missing examples are not invented, and external example URLs are not retrieved.

Are inherited parameters retained?

Path-level parameters are included, with operation-level parameters overriding matching names and locations. Check local references in the original specification because they are not resolved.