Why diffcat?

There are good diff tools already: delta, difftastic, lazygit, tig. diffcat is narrower on purpose, its main focus is on making the git diff view experience delighful.

Features

• TUI with native vim keybindings
• GitHub-style diffs: green/red tints, line-number gutters, syntax highlighting, surrounding-line expansion
• Unified or side-by-side view (s); a theme picker (t) with 8 color themes, light/dark, file-type icons, and a reduce-motion toggle
• Auto-detected base, or any ref via --base
• e opens the file under the cursor in your own editor, at the line you were reading
• Commit history view with per-commit diffs
• Stats dashboard (S): contribution calendar, per-author ranking, activity charts, streaks, and a human-vs-AI split that names each agent — over the last week, month, 6 months, year, or all time (1–5, or [/])

Demo

Install

Prebuilt binary (no Go required). Download the tarball for your platform from the latest release (darwin-amd64, darwin-arm64, linux-amd64, linux-arm64), then:

tar -xzf diffcat-*-darwin-arm64.tar.gz   # match the file you downloaded
sudo mv diffcat /usr/local/bin/

With Go (1.25+):

go install github.com/trebaud/diffcat/cmd/diffcat@latest

From source:

git clone https://github.com/trebaud/diffcat.git && cd diffcat && ./scripts/install.sh

Commands

diffcat [path] [--base <ref>]         # launch the TUI (path defaults to .)
diffcat files [path] [--base <ref>]   # print the changed-file list, non-interactive

--base, -b <ref> overrides the base. It accepts any git ref: a branch, remote branch, tag, or commit.

diffcat -b develop
diffcat -b origin/main
diffcat -b v1.2.0
diffcat -b 3f9a1c2

Without --base, the base is auto-detected: origin/HEAD, else master, else main. The detected name is then resolved to whichever of the local branch and its remote-tracking counterpart forked from HEAD later, so an unfetched local master doesn't report everything that landed on origin/master since as part of your branch. When the two differ, the header and the history divider name the ref actually being measured against (e.g. origin/master).

Open in your editor

Press e on a file (or on a line in the diff) to hand the terminal to your editor, opened at that line. diffcat suspends while the editor runs and reloads the diff from disk when you quit it, so an edit shows up immediately.

It's vim unless you say otherwise. Name another in ~/.config/diffcat/config.json:

{
  "editor": "nvim"
}

The value is a command, so flags are fine ("code -w", "emacsclient -nw"). Precedence is --editor → DIFFCAT_EDITOR → config → $VISUAL → $EDITOR → vim.

The line number is passed the way each editor expects it: +N for the vim family, nano, micro, kak and emacs; --goto file:N for VS Code and its forks; file:N for Sublime, Helix and Zed. Anything else is handed just the path.

Themes & appearance

Press t in the TUI for the theme picker: arrow through the themes with a live preview, T flips light/dark, i cycles the file-type icon set, m toggles animations, ↵ keeps the choice (persisted), esc reverts. Your selection is saved to ~/.config/diffcat/config.json and restored on the next run.

You can also set appearance up front, via flags or environment variables:

diffcat --theme dracula           # github (default), dracula, nord, catppuccin,
                                  # gruvbox, tokyonight, solarized, monochrome
diffcat --icons nerd              # ascii (default), unicode, nerd (needs a Nerd Font)
diffcat --no-anim                 # freeze the nyan cat, pulse, and shimmer

DIFFCAT_THEME=nord diffcat        # env equivalents: DIFFCAT_THEME, DIFFCAT_ICONS,
                                  # DIFFCAT_NO_ANIM

Precedence is flag → environment → saved config → terminal auto-detection. NO_COLOR is honored: when set, diffcat forces the monochrome theme and freezes all motion.

License

MIT, see LICENSE. Built on Bubble Tea, Lip Gloss, Cobra, and Chroma.