Code Review
Commercial use OK
380+ models
No watermark
No sign-up needed
Model:
+ GPT-5, Claude, Gemini
Paste code (or upload a file), pick a review focus, and get back a severity-graded review with file-line references. Self-hosted Qwen2.5-Coder is free under the daily pool; premium Claude Sonnet 4 / GPT-5 are better for security audits and large multi-file reviews.
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Get instant code reviews with free AI. Find bugs, security issues, and improvements.
How to Use Code Review
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 Review — FAQ
Paste code (or upload a .py / .js / .go / .rs / etc. file), pick a review focus — security audit, performance, best practices, test gaps, refactor, beginner-friendly explainer — and get back a severity-graded review with line-number references. Works on 15+ languages.
Copilot review is inside your PR; Free.ai Code Review is ad-hoc — paste anything, pick the focus, get a review in ~10 seconds. No repo connection, no install. Use Free.ai for pre-PR cleanups, one-off audits, and code you haven't committed yet.
CodeRabbit and SonarCloud are CI/repo-integrated — they hook GitHub/GitLab and post PR comments. Free.ai Code Review is browser-based — paste a snippet, get the review, no account required. Complement, not replace — use Free.ai for rapid iteration, CodeRabbit/Sonar as your CI gate.
Qwen 3 Coder (self-hosted, free-pool) nails ~95% of reviews. Pick DeepSeek R1 for deep-reasoning audits. Upgrade to premium Claude Sonnet 4 or GPT-5 when you need multi-hundred-line reviews, complex security audits, or extended-context reasoning across a large file.
OWASP top 10 (SQL injection, auth bypass, XSS, CSRF, SSRF, insecure deserialization, etc.), secret handling (hardcoded keys, credentials in logs), input validation, known-vulnerable dependencies (where detectable from imports), and output encoding issues. Severity-graded.
Yes. Pick "Performance" focus. The reviewer looks for algorithmic-complexity issues (O(n²) where O(n log n) applies), N+1 queries, unnecessary allocations inside hot loops, blocking I/O in async code, and redundant work. Findings quantify impact where possible.
Refactor mode produces BEFORE/AFTER snippets. For one-click fixes, use the separate Refactor tool at /code/refactor/ — it generates a full rewrite. Code Review is for DIAGNOSIS; Refactor is for the FIX.
Code is sent to the AI model, processed, and discarded. Not stored, not used for training. If you need maximum privacy, pick Qwen 3 Coder (self-hosted on our GPUs — never leaves our servers).
Paste up to 10,000 characters (~150 lines of average code) on the self-hosted path. Premium Claude / GPT-5 models support up to 200K characters — upgrade if you need full-file reviews.
Yes — switch to the Upload tab. Accepts .py .js .ts .jsx .tsx .java .go .rs .cpp .c .h .cs .rb .php .swift .kt .sh .sql and more, up to 500KB. File is read client-side and previewed in the paste area before submit.
Asks the model for every finding, with code examples for each suggested fix, alternatives, and citations to best-practice sources. Costs ~3× more tokens — premium models only (the self-hosted context window cannot hold the full expanded output).
Yes — POST to /v1/chat/ with a system prompt describing your review focus and the code as the user message. See /api/ for the full spec. Review results are also shareable via /share/<token>/.
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