Your AI writes code fast.
Diff Warden keeps it correct.
A GitHub bot that reads every PR diff, flags the fast-but-risky changes, explains the danger in plain English, and suggests slower-but-safer rewrites with tests. It optimizes for correctness-per-merge, not speed.
Free tier: 1 repo, 30 reviews/month. No credit card.
“You wrote it faster, then debugged it slower.”
AI generates plausible code in seconds — and quietly buries swallowed errors, unvalidated input, hardcoded secrets, and deleted tests inside it. Those minutes you saved come back as production incidents. Diff Warden catches them at the diff, where they’re still cheap to fix.
See it on a real diff
Paste any git diff — or pick a sample below — and get the same review the bot posts on your PRs. Runs instantly, stores nothing.
Runs entirely on the diff text. Nothing is stored. No GitHub install needed.
How it works
Reads every PR diff
Install the GitHub App. On each opened or updated PR, Diff Warden pulls the diff automatically.
Explains the risk in plain English
Each finding gets a severity, why AI tends to write it, and a correctness-per-merge score for the whole PR.
Suggests safer rewrites with tests
Not just 'this is bad' — a concrete safer approach and the exact test to add. Pro adds inline auto-fixes.
“We merged an AI PR that swallowed every payment error for two days. Diff Warden would have flagged it on line one.”
— Early access founder, fintech startup
Trusted by solo founders and small dev teams shipping with Copilot, Cursor & Claude Code
Simple pricing
Start free. Upgrade when AI code becomes your default.
Free
For solo devs trying it on one project.
- 1 repository
- 30 PR reviews / month
- Plain-English risk summaries
- Correctness-per-merge score
- Public + private repos
Pro
Most popularFor teams shipping AI code every day.
- Unlimited private repositories
- Unlimited PR reviews
- Inline auto-fix suggestions
- Suggested safer rewrites with tests
- Priority analysis queue
- Email support