diffviewer

A fast, keyboard-driven git diff reviewer for macOS and Linux. Built for the loop where an agent writes code and you read every file before staging it.

Why

• Files ordered by what matters. Changes are grouped by layer — Domain → Use cases → Application → Infrastructure → Other — with tests last. Layer names are configurable, so it works for any folder convention.
• Stage as you review. s stages the current file and jumps to the next unstaged one. The checkbox is your "reviewed" marker. Commit from the same window.
• Real side-by-side diffs. Syntax highlighting, word-level change emphasis, hunk navigation, collapsible unchanged regions, and independent horizontal scrolling per pane so long lines never push the other side away.
• ⌘-click to see a definition. A built-in Python symbol index follows imports (including package re-exports) and opens the definition in a peek panel, without leaving the diff. Chain further with more ⌘-clicks, or open it in your editor.
• Tabs, one window. dw <dir> from any terminal opens the repo as a new tab in the running window. ⌘1–⌘9 switch tabs.
• Always live. The working tree is polled, so the list updates as files change on disk.

Install

One line (macOS universal, Linux x86_64/aarch64):

curl -fsSL https://raw.githubusercontent.com/sleipner42/diffviewer/main/install.sh | sh

This puts diffviewer and the dw launcher in ~/.local/bin (override with DIFFVIEWER_INSTALL_DIR).

Homebrew:

brew install sleipner42/tap/diffviewer

From source (needs a Rust toolchain; on Linux also GTK 3, xkbcommon and Wayland/X11 development headers):

git clone https://github.com/sleipner42/diffviewer
cd diffviewer
./scripts/install.sh

Usage

dw              # review the repo containing the current directory
dw ~/code/app   # open another repo as a new tab
dw update       # update to the latest release

dw returns immediately; the app runs detached. If diffviewer is already open, the directory is added as a tab in the existing window.

Keys

On Linux, Ctrl replaces ⌘.

Updates

The app checks GitHub Releases on startup and shows an Update button in the status bar when a newer version exists. dw update does the same from the terminal, and Homebrew installs update with brew upgrade diffviewer.

Configuration

~/.config/diffviewer/config.toml — every key is optional. See config.example.toml for the full set:

tiers = [
  { name = "Domain", markers = ["domain"] },
  { name = "Use cases", markers = ["use_cases", "usecases", "use-cases"] },
  { name = "Application", markers = ["application", "app", "api", "presentation"] },
  { name = "Infrastructure", markers = ["infrastructure", "infra", "adapters"] },
]
test_markers = ["tests", "test", "__tests__", "spec", "specs"]
hide_tests = false
editor_command = "zed {path}:{line}"

A file belongs to the innermost directory that matches a tier marker; anything else lands in Other. Tests are detected by directory (tests/, spec/, …) or by name (test_*.py, *_test.py, *.spec.ts, …).

How it works

Everything goes through the git CLI, so hooks, credentials and your global config behave exactly as in the terminal. Diffs are always HEAD → working tree, regardless of what is staged, so you see the full change the author made.

Releases are built by GitHub Actions from tags (v*); the installer and the in-app updater both fetch from GitHub Releases.

Development

cargo run -- path/to/repo
cargo test

The code is split into domain (diffing, importance ordering, Python symbol index), application (review service, repository port), infra (git CLI, config, highlighting, background workers) and ui (egui).