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Your next review, already waiting.
Your PRs first. Requested reviews next. An inbox that stays in sync with GitHub, with pins for the repos and pull requests you keep coming back to.
- Automatic repo discovery
- Live PR updates
A new perspective on pull requests
See the story
in every diff.
− Less piecing it together.+ More understanding.
Review GitHub PRs with your Claude Code or Codex agent beside the code.
macOS · Apple silicon / Early alpha
Explore the review workflow
Important code, with the explanation beside it.
Explore the sampleClaude’s deeper code notes connect to the actual diff. The narrow index keeps chapters, conversations, and reviewed sections within reach.
Get the story before the line-by-line review.
Explore the sampleA real Claude Fable 5 walkthrough of a 20-file sample PR: database migrations, access policies, API changes, localization, and more.
Keep your question attached to the code.
Explore the sampleSelect lines, open the + composer, and ask Claude what to check before shipping a delete endpoint. Scroll through its real answer, then continue the same conversation in PR chat. AI questions stay private; author feedback starts as an unpublished draft.
Full app recording · no audioView GIFDownload video
Continue the discussion alongside your review.
Explore the sampleThe same conversation is available in PR chat, with its code context beside the composer. Copy a response or the whole thread with its context whenever you need it.
Full-window recordings and screenshots from the real macOS app using sample PRs in the Diff City repo. Guide and replies generated with Claude Code · Fable 5. Recordings are condensed; AI waiting time is shortened. Other account avatars are hidden for privacy. Sample code is intentionally flawed and available in the source repo for trying the review workflow yourself.
GitHub/ Codex/ Claude Code
From open PR to informed feedbackA review that reads
A review that reads
like a conversation.
For your own work, your teammate’s work,
and the changes that deserve a closer look.
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The important changes come first.
Read a rich overview, then scroll through a guided walkthrough. Follow explanations beside the code, inspect deeper notes, and expand routine changes when you need them.
- Code notes + naming decisions
- Markdown + Mermaid
03
Think it through. Then send it.
Ask about a line, a range, or a single variable. Run independent conversations with your AI. Keep notes private, or turn an answer into a draft for the PR author.
- Concurrent conversations
- Explicit GitHub publishing
Built for the second lookStay in the flow.
Stay in the flow.
Keep the context.
The little things that make a big diff feel manageable.
Review the delta
See just the changes since your last review, or return to the full PR.
Room for the code
Fast, virtualized diffs. Sticky file headers. A minimap for long files and a chapter rail that tracks what you’ve reviewed.
More than one perspective
Generate guides with Codex and Claude, then switch between them.
Make it your workspace
Light and dark themes, accessible controls, and conversations you can copy with their code context.
Public alpha for macOSYour next review
Your next review
could feel different.
Diff City is starting on Mac. Built with Tauri, designed around GitHub, and open source under the MIT license.
Follow the project on GitHub Made by Christopher Smothers. Contributions welcome.diff.city
Diff City for Mac
macOS 14+ · Apple siliconUnsigned alpha · not notarized. macOS requires approval on first launch. Install instructions · Release notes & checksums
Bring your GitHub CLI login and a local Codex or Claude Code login. No Diff City account required.
A few things to know.
Does my code stay on my Mac?
Your review workspace, notes, and guides are stored locally. When you ask AI or generate a guide, relevant code and context are sent to your chosen provider through your local Codex or Claude Code login. GitHub drafts stay private until you explicitly publish them.
Can I use my existing AI subscription?
Diff City connects to the local Codex and Claude Code tools you’re already signed into. Model availability, usage limits, and billing follow that provider account. You can choose a default model and generate separate guides with different models.
Is Diff City open source?
Yes. Diff City is MIT licensed and developed in public at github.com/crs48/diffcity. You can inspect the code, build it yourself, and contribute improvements.
What platforms will it support?
The current alpha targets Apple silicon Macs running macOS 14 or later. Windows, Linux, and Intel Mac downloads are not available yet.