DiffHub

A cmux git diff viewer for reviewing a whole branch, with inline comments you can hand to an agent

Run one command inside any git repository and DiffHub serves a GitHub-style diff of your working tree at localhost:2047.

Demo

Browse any public GitHub pull request in the hosted viewer, with nothing installed.

Install

npm install -g diffhub

Or run it without installing: npx diffhub@latest.

Quickstart

Run inside any git repository.

# Review the current branch in a cmux browser split
diffhub cmux

# The same viewer in your default browser
diffhub

# Compare against a different base branch
diffhub cmux --base develop

# Review a repository in another directory
diffhub cmux --repo ~/Code/mblode/cmux

The default view is touched: HEAD versus the working tree, including untracked files. Merge-base scopes (all, committed) are available from the status bar, and --base still selects the comparison branch, preferring origin/main so unpushed commits show up. A watcher marks updates available; press r to refresh. diffhub cmux uses a repo-derived port in 20000–29999 instead of 2047.

For a complete review loop, see Review agent-written code in cmux.

Commands

Command	Description
diffhub	Open DiffHub in your default browser
diffhub cmux	Open DiffHub in a cmux browser split
diffhub serve	Same as diffhub, starts the local web app

Options

diffhub and diffhub serve

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

diffhub cmux

Flag	Default	Description
-r, --repo <path>	cwd	Path to the git repository
-b, --base <branch>	auto	Base branch to diff against

Keyboard shortcuts

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

Notes

• Node.js 20.11+ or Bun 1.0.23+, and a git repository (git rev-parse --show-toplevel must succeed).
• cmux mode expects cmux.app installed on macOS at /Applications/cmux.app.
• Comments live in .git/diffhub-comments.json in the repository you are reviewing, and copy out as a markdown review prompt for a coding agent.

License

MIT

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Crafted by Matthew Blode