Code

Generate API documentation from code

Paste your API code or endpoint details and get complete documentation with examples and error codes.

For the best results: Paste your API endpoint code or describe your routes, parameters, and responses. The AI generates clean documentation with examples.

AI can make mistakes. Check important information before relying on it.

FREE · PRIVATE · NO SIGN UP REQUIRED · NO ACCOUNT NEEDED

What is API Docs Generator?

API Docs Generator is a free AI coding assistant that turns your API code or endpoint details into complete documentation with examples and error codes. Each request is handed to a code-specialized model chosen for the task, returning working code, bug fixes, and explanations in any programming language in seconds. You paste and go, with no login and nothing to install, and the code you share is not retained once the session ends.

✦Paste code and go, no login, nothing to install
✦Code-specialized models are selected per request automatically
✦Your code is not retained after the session ends

Models: It routes across strong coding models including Llama, Gemini and Mistral families, picking the best available one per request. The exact model used is shown after every response.

See it in action

Your team just shipped an internal ordering endpoint and the frontend developers keep asking how to call it.

What you type

POST /api/v1/orders — requires Bearer token. Body: customerId (int), items (array of {sku, qty}). Returns the created order. Can fail if the token is bad or an item is out of stock.

What you get

### POST /api/v1/orders Create a new order. Requires `Authorization: Bearer <token>`. Request body: | Field | Type | Required | |-------|------|----------| | customerId | integer | yes | | items | array<{sku, qty}> | yes | Example: curl -X POST /api/v1/orders -H "Authorization: Bearer TOKEN" \ -d '{"customerId":42,"items":[{"sku":"WIDGET-1","qty":2}]}' Errors: 401 invalid_token · 409 out_of_stock · 422 validation_failed

Tip: Docs are only trusted when the error codes are honest, so list the failure responses your handler can actually return, not just the happy path. Feed the generator your validation and try/catch blocks and it will map each thrown case to the right status code.

Use cases

What people use it for

Document a REST API you built months ago before handing the project to another developer.

Add proper examples and error codes to a partner-facing API before an integration starts.

Turn rough endpoint notes into readable reference docs for your team's internal wiki.

Who uses API Docs Generator?

Solo API builders

turning a set of route handlers into reference docs so early users can integrate without emailing them every question

Backend teams

drafting a first documentation pass from existing controllers to hand to a technical writer for polish

Integration partners

writing clear internal notes on a third-party API by pasting its example requests and getting a structured reference

How it works

1Paste your code or describe what you need built.
2A code-specialized model writes, fixes, or explains it.
3Copy the code out, or ask follow-ups to iterate on it.

Tips for the best results

Paste the actual route handlers or a sample request and response, not just endpoint names, so the docs describe real parameters instead of inventing them.
Include your error responses and status codes; a good reference tells integrators what a 400 or 401 looks like, and the tool can only document the ones you show it.
Specify the output format you need, whether Markdown, OpenAPI or a table, before generating, so it fits your docs site without a manual rewrite.
Provide one worked example per endpoint; a concrete request and response makes the generated samples far more useful than abstract field lists.
Review any described behavior against your code, since the tool documents what your input implies and cannot see logic you did not paste.

FAQ

Frequently asked questions

Should I paste actual code or describe my endpoints?

Route handlers or controller code give the best results, because parameters, validation and response shapes can be read straight from them. No code handy? List each endpoint's method, path, parameters and a sample response. The quality of the documentation tracks the quality of what you feed in.

Will it make up details it can't see?

It can, gaps in your input get filled with plausible assumptions, and plausible is not the same as correct. Default values, error codes and field types are the usual suspects. Review the draft against your API's real behavior before publishing; wrong documentation costs more trust than none at all.

What does the generated documentation include?

For each endpoint: a summary of what it does, parameters with types and whether they're required, example requests and responses, and the error codes callers should handle. You can ask for more of any one thing (extra response examples, say) or a terser reference style, in a follow-up.

Can I get the output in a specific structure, like OpenAPI?

Ask for the shape you need and it writes to that: markdown tables for a wiki, OpenAPI-style YAML, or plain prose for a getting-started guide. It's all text for you to copy into wherever your docs live, so the structure is entirely yours to dictate.

How do I handle the authentication section?

Describe your scheme (API key in a header, bearer tokens, an OAuth flow) and it drafts the auth documentation with example headers included. Use obvious placeholders like YOUR_API_KEY in everything you paste and publish; real credentials should never appear in a prompt or in your docs.

Is this API documentation generator free?

Yes, free with no account, sign-up or payment and no limit behind a login. Paste your endpoint code or details and get structured documentation you can copy out. It only documents what you provide, so the more complete your input, including routes, parameters and sample responses, the more complete and accurate the output.

Can it write example requests in curl or a specific language?

Yes. Ask for code samples and it produces example requests as curl commands or in a language you name, such as JavaScript fetch or Python requests, matched to your endpoints. Give it a real sample request or response so the examples use plausible field names and values rather than generic placeholders.

What output format does the documentation come in?

You get clean Markdown you can paste into a README, a wiki or a docs site. Ask for a specific structure, such as an OpenAPI-style layout, an HTML table or a particular heading order, and it will follow it. State the format so you do not have to reformat the result by hand.

What are the usage limits?

Code tools are text tools, so they are unmetered during the current free launch phase, iterate on a bug or generate as many drafts as the work needs. A short per-minute limit guards against scripted abuse only. Paid plans with higher limits and priority model access are coming soon.

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