Code Documentation
Commercial use OK
380+ models
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Model:
+ GPT-5, Claude, Gemini
Paste code (or upload a file) and get inline docstrings, type-aware comments, and an optional README — in your choice of 5 styles (Google, NumPy, reST/Sphinx, JSDoc, plain). Self-hosted Qwen 3 Coder is free under the daily pool; premium Claude/GPT-5 handle long files better than DocStringGenerator or Mintlify Writer.
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Generate code documentation with free AI. Docstrings, comments, and API docs.
How to Use Code Documentation
1
Enter your input
Type text, upload a file, or describe what you want. No account needed.
2
Click generate
Our AI processes your request in seconds using the best open-source models.
3
Download & share
Download, copy, or share your result. Free for personal and commercial use.
Use this tool via API
Automate this tool from your own code. OpenAI-compatible REST endpoint, Bearer-token auth, no extra SDK required. Token costs match the web interface.
curl -X POST https://api.free.ai/v1/chat/ \
-H "Authorization: Bearer sk-free-..." \
-H "Content-Type: application/json" \
-d '{"model": "qwen-coder", "messages": [{"role": "user", "content": "Write a Python function that reverses a string."}]}'Code Documentation — FAQ
Paste source (or upload a file up to 500KB) and get back the same code with docstrings, type-aware comments, and — optionally — a README.md and API.md reference. Pick one of 5 docstring styles (Google / NumPy / reST-Sphinx / JSDoc-TSDoc / plain) and 5 output scopes (docstrings only, +inline, +README, +API ref, full pack). Code body stays byte-for-byte identical; only docstrings and comments are added.
Mintlify Writer is a free VSCode extension that does inline docstrings only — no README, no API ref. DocuWriter.ai charges $19/mo for unlimited and gates style-switching behind paid tiers. Tabnine adds short summaries inline as part of its $12/mo Pro plan. Free.ai runs through the daily token pool with no monthly subscription, supports all 5 styles in the free tier, and can emit a README + full API reference in one shot which the IDE plugins cannot.
No — the system prompt forbids renaming, reordering, or modifying any logic. Only docstrings and comments are added. The "Original" view in the result panel lets you confirm by switching back; copy-paste the documented version into your file with confidence.
Google for Python projects new in 2018+ (mkdocs / pdoc render it cleanly). NumPy for scientific Python (matplotlib, scikit-learn convention). reST/Sphinx for older Python projects already on Sphinx autodoc. JSDoc/TSDoc for JavaScript/TypeScript (works with VSCode IntelliSense and TypeDoc). Plain when you want one short comment line per function and no formal blocks.
Yes — pick "Docstrings + README.md" or "Full pack" scope. The README includes project name, one-line tagline, install command (pip / npm / cargo / go-get inferred from the language), 30-second quickstart, key API call, and a license placeholder. For richer marketing-grade README copy, chain into our /code/readme/ tool after.
API reference (Markdown) lists every public symbol grouped by file/class with signature, purpose, parameters, returns, and an example call — ready to paste into a `docs/` folder, ReadTheDocs, or a GitHub Pages site. Inline docstrings live in the code itself. Pick "Full pack" to get both at once.
Qwen 3 Coder (default, free pool) handles ~95% of files under 200 lines well. DeepSeek R1 for files where you want deep reasoning about edge cases the docstring should mention. Premium Claude Sonnet 4 / GPT-5 for whole-package documentation runs over 1,000 lines — they hold larger context and produce more consistent style across files.
Yes — when "Add type info" is checked the model uses existing type annotations where present and infers reasonable types from usage where not. Inferred types are clearly placed in the docstring (Args section / @param tag) so they remain reviewable. The actual code annotations are not added by Code Documentation — use /code/refactor/ with the "Type safety" goal for that.
Per call, paste up to 12,000 characters (~180 lines). For multi-file projects, run file-by-file (chain the same code through Code Documentation, then click "Generate tests" to get tests for the documented version). Or use the API for batch jobs — POST to /v1/chat/ in a loop.
Code is sent to the model, processed, and discarded. Not stored, not used for training. For maximum privacy pick Qwen 3 Coder — self-hosted on our GPUs, your code never leaves Free.ai infrastructure. External premium models (Claude, GPT-5) route through their respective providers under their data-handling terms.
Python, JavaScript, TypeScript, Java, C++, C, C#, Go, Rust, Ruby, PHP, Swift, Kotlin, Shell/Bash, SQL, HTML/CSS — 16+ in the picker, with auto-detect for everything else the model recognizes (Lua, Elixir, Haskell, Scala, Dart, R, MATLAB, Perl).
Yes — POST to /v1/chat/ with the documentation system prompt (style + scope + extras) and the code as the user message. Useful for plugging documentation into a CI step or a pre-commit hook. See /api/ for snippets.
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