DiffHub

Git diff viewer for cmux. Opens in a browser split and shows HEAD versus the working tree by default (touched), with status-bar scopes for merge-base and staged/unstaged views, split/unified diffs, and inline comments. A watcher marks updates; refresh is manual (r).

Install

npm install -g diffhub

Or run without installing:

npx diffhub

Usage

Run inside any git repository:

diffhub

Opens http://localhost:2047 and shows HEAD versus the working tree. Use --base to pick the comparison branch (main, master, develop, or dev, auto-detected). Switch scopes in the status bar: all, committed, staged, unstaged, touched.

# Use a different base branch
diffhub --base develop

# Point at a repo in another directory
diffhub --repo ~/projects/my-app

# Use a different port
diffhub --port 3000

# Don't open the browser automatically
diffhub --no-open

Features

• Working-tree diff — defaults to touched (git diff HEAD plus untracked); status bar switches all / committed / staged / unstaged / touched
• Split and unified views — toggle with s, keyboard-navigable with j / k
• Inline comments — add [must-fix], [suggestion], [nit], or [question] notes on any diff line; copy all comments as a formatted prompt
• Copy path — file headers expose a copy-path control
• Manual refresh — watches local file changes and marks updates available; press r or the status-bar refresh control
• File sidebar — filter files with / or t, see per-file +/- stats at a glance

Development notes

• The standalone CLI injects DIFFHUB_REPO into the Next.js server process.
• Local development can also point at a repo through DIFFHUB_REPO or the /tmp/diffhub-active-repo pointer file used by diffhub-point.
• The app ships a standalone Next.js build via bin/diffhub.mjs, not next start.

Keyboard shortcuts

| Key | Action | | ----------- | ------------------------------------ | | j / k | Next / previous file | | s | Toggle split / unified view | | c | Collapse or expand the selected file | | Shift+C | Collapse all files | | Shift+E | Expand all files | | / or t | Focus file filter | | r | Refresh the diff | | F2 | Toggle the Diff stats panel |

Options

| Flag | Default | Description | | --------------------- | ------- | --------------------------- | | -p, --port <port> | 2047 | Port to serve on | | -r, --repo <path> | cwd | Path to the git repository | | -b, --base <branch> | auto | Base branch to diff against | | --no-open | — | Skip automatic browser open |

Requirements

• Node.js 20.11+ or Bun 1.0.23+
• A git repository (git rev-parse --show-toplevel must succeed)

License

MIT