What is DiffGuardian?
AI code review for macOS, Windows and Linux that reads every pull request against your whole repository — and keeps the merge decision with you.
DiffGuardian is a native desktop app for reviewing pull requests, available for macOS, Windows and Linux. It reads a change against your entire repository — not just the lines in the diff — breaks it into the features it actually ships, and explains each one in plain English.
It exists because code generation got fast and comprehension did not. An agent can open a 5,000-line pull request across forty files before lunch. That is more than anyone can genuinely read, so "approve" quietly turns into a formality. DiffGuardian's job is to make understanding a change faster than rubber-stamping it.
#What it does
| Capability | What it means | Plan |
|---|---|---|
| Whole-repo review | The AI sees the change in the context of the surrounding codebase, so it catches ripple effects and broken contracts a diff-only read misses. | Basic (5/month) |
| Writing the review | Draft comments on the diff, adopt the AI's suggestions as your own, and submit the lot as one review under your own token. | Basic |
| Diagrams | Dependency graphs and stack maps drawn from your real call graph, not hand-authored. | Basic |
| Trace It | A large PR is split into the discrete features it ships. You step through one at a time, across every file it touches. | Pro |
| Ask and Explain | Question the pull request in front of you, or select a snippet and have just that explained. | Pro |
| Analyze Project | Ask how something works anywhere in the repo and get an answer grounded in your actual code, with a diagram when it helps. | Pro |
| Knowledge bases and MCP | Ground answers in your own documents, and let a review call your own tools. | Pro |
| Voice | Dictate comments, and have findings and answers read back to you. | Pro |
| Cloud AI providers | Anthropic, OpenAI, Gemini and Kimi, on your own key. Local models are on every plan. | Pro |
Pro features are never hidden on Basic — they stay where you expect them and explain themselves when you reach for one. See Plans.
#What it is not
DiffGuardian is not another line-by-line linter, and it is not an autonomous approver. It never merges anything, and nothing reaches your code host unless you send it: an AI review produces suggested comments, and a verdict is submitted only when you pick one and press the button yourself. The one gate that still matters — the decision to merge — stays with you.
#How it is built
DiffGuardian runs on your own machine. Your repositories, diffs, and source never pass through DiffGuardian's servers. You review either entirely on your own machine using a local model, or with your own AI provider key, under your own agreement with that provider. Your knowledge bases, MCP connections and code standards are configuration held on your device, not account state we store.
The hosted DiffGuardian service handles only sign-in, your plan, billing, and service status. See Privacy and data handling for the full breakdown of what leaves your machine.