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difit is a CLI tool that lets you view and review local git diffs with a GitHub-style viewer. In addition to clean visuals, comments can be copied as prompts for AI. The local code review tool for the AI era!

Try it first

npx difit  # View the latest commit diff in WebUI

Install and use

npm install -g difit
difit  # View the latest commit diff in WebUI

difit <target>                    # View single commit diff
difit <target> [compare-with]     # Compare two commits/branches
difit --pr <github-pr-url>        # Review GitHub pull request

difit          # HEAD (latest) commit
difit 6f4a9b7  # Specific commit
difit feature  # Latest commit on feature branch

difit @ main         # Compare with main branch (@ is alias for HEAD)
difit feature main   # Compare branches
difit . origin/main  # Compare working directory with remote main

difit supports special keywords for common diff scenarios:

difit .        # All uncommitted changes (staging area + unstaged)
difit staged   # Staging area changes
difit working  # Unstaged changes only

difit --pr https://github.com/owner/repo/pull/123

difit automatically handles GitHub authentication using:

1. GitHub CLI (recommended): If you're logged in with gh auth login, difit uses your existing credentials
2. Environment Variable: Set GITHUB_TOKEN environment variable
3. No Authentication: Public repositories work without authentication (rate-limited)

For Enterprise Server PRs, you must set a token generated on YOUR Enterprise Server instance:

1. Go to https://YOUR-ENTERPRISE-SERVER/settings/tokens
2. Generate a personal access token with appropriate scopes
3. Set it as GITHUB_TOKEN environment variable

By using a pipe to pass unified diffs via stdin, you can view diffs from any tool with difit.

# View diffs from other tools
diff -u file1.txt file2.txt | difit

# Review saved patches
cat changes.patch | difit

# Compare against merge base
git diff --merge-base main feature | difit

# Review an entire existing file as newly added
git diff -- /dev/null path/to/file | difit

difit includes a review comment system that makes it easy to provide feedback to AI coding agents:

1. Add Comments: Click the comment button on any diff line or drag to select a range
2. Edit Comments: Edit existing comments with the edit button
3. Generate Prompts: Comments include a "Copy Prompt" button that formats the context for AI coding agents
4. Copy All: Use "Copy All Prompt" to copy all comments in a structured format
5. Persistent Storage: Comments are saved in browser localStorage per commit

src/components/Button.tsx:L42   # This line is automatically added
Make this variable name more descriptive

For range selections:

src/components/Button.tsx:L42-L48   # This line is automatically added
This section is unnecessary

• JavaScript/TypeScript: .js, .jsx, .ts, .tsx
• Web Technologies: HTML, CSS, JSON, XML, Markdown
• Shell Scripts: .sh, .bash, .zsh, .fish
• Backend Languages: PHP, SQL, Ruby, Java, Scala
• Systems Languages: C, C++, C#, Rust, Go
• Mobile Languages: Swift, Kotlin, Dart
• Others: Python, Protobuf, YAML, Solidity, Vim script

difit automatically identifies and collapses generated files to keep your view clean. This includes:

• Lock files (package-lock.json, go.mod, Cargo.lock, Gemfile.lock, etc.)
• Minified files (*.min.js, *.min.css)
• Source maps (*.map)
• Generated code:
  • Orval (*.msw.ts, *.zod.ts, *.api.ts)
  • Dart (*.g.dart, *.freezed.dart)
  • C# (*.g.cs, *.designer.cs)
  • Protobuf (*.pb.go, *.pb.cc, *.pb.h)
• Frameworks:
  • Ruby on Rails (db/schema.rb)
  • Laravel (_ide_helper.php)
  • Gradle (gradle.lockfile)
  • Python (uv.lock, pdm.lock)
• Generic generated files (*.generated.cs, *.generated.ts, *.generated.js)
• Content-based detection:
  • Files containing @generated marker
  • Files containing DO NOT EDIT header
  • Language-specific generated headers (Go, Python, etc.)

# Install dependencies
pnpm install

# Start development server (with hot reload)
# This runs both Vite dev server and CLI with NODE_ENV=development
pnpm run dev

# Build and start production server
pnpm run start <target>

# Build for production
pnpm run build

# Run tests
pnpm test

# Lint and format
pnpm run lint
pnpm run format
pnpm run typecheck

• pnpm run dev: Starts both Vite dev server (with hot reload) and CLI server simultaneously
• pnpm run start <target>: Builds everything and starts production server (for testing final build)
• Development mode: Uses Vite's dev server for hot reload and fast development
• Production mode: Serves built static files (used by npx and production builds)

• CLI: Commander.js for argument parsing with comprehensive validation
• Backend: Express server with simple-git for diff processing
• GitHub Integration: Octokit for GitHub API with automatic authentication (GitHub CLI + env vars)
• Frontend: React 18 + TypeScript + Vite
• Styling: Tailwind CSS v4 with GitHub-like dark theme
• Syntax Highlighting: Prism.js with dynamic language loading
• Testing: Vitest for unit tests with co-located test files
• Quality: ESLint, Prettier, lefthook pre-commit hooks

• Node.js ≥ 21.0.0
• Git repository with commits to review

MIT