JayJay

JayJay is a native GUI for Jujutsu on macOS and Linux, with a Windows alpha and reusable Rust libraries for diff and review tooling.

• macOS: native SwiftUI app.
• Linux: GPUI app. Its macOS build is for development.
• Windows: GPUI alpha, available from the Microsoft Store or as a portable ZIP.
• Rust libraries: diffing, review state, repository operations, and app bindings.

JayJay App

JayJay is a fast, keyboard-friendly GUI for people who use jj every day.

Highlights

• History: a DAG of changes with bookmarks, tags, conflicts, divergent changes, and other workspaces' working copies; a revset bar with completion and presets; drag a change or a whole selection to rebase it, or drag bookmarks and @ to move them.
• Diffs: unified and side-by-side with syntax highlighting, word-level changes, expandable context, and rename detection; rich previews for images, SVG, Markdown, HTML, notebooks, CSV/TSV, SARIF, and property lists; edit working-copy files in place.
• Review: file and per-hunk review marks that survive edits and rebases, line-anchored review notes, and a jayjay review CLI that lets coding agents read and resolve notes or pre-mark mechanical files.
• Compare and inspect: interdiff between revisions or bookmarks, divergent-version compare, annotate, file history, and change evolution (jj evolog) with Restore this version.
• Split work: select files, hunks, or line ranges and move them into a child, a sibling, or the working copy; split by review state; jj split --tool jayjay opens the same editor.
• Conflicts: a merge editor with per-conflict Accept Left, Right, or Base, a raw marker mode, one-click Use Ours and Use Theirs, and an explicit jj resolve --tool handoff.
• Operations: new, edit, describe, squash, split, rebase (including onto trunk), merge, parallelize, duplicate, absorb, revert, abandon, push, fetch, and undo from the operation log.
• Workspaces: create, switch in the current window, and forget workspaces; check out a pull request as a new workspace; the Repo Overview window shows every lane of mutable work and what needs attention.
• Bookmarks and forges: Bookmark Manager with remote sync state and cleanup; PR/MR links and CI status for GitHub, GitLab, Codeberg, and Cursor Origin; stacked PRs and MRs.
• AI commit messages from Codex CLI, Claude CLI, or Apple Intelligence, in the order you choose.
• Keyboard friendly: a command palette that also runs raw jj commands and finds help topics, Tab focus cycling, and shortcuts for everyday actions.
• Integrations: external editors and terminals, pinned and recent repositories, multiple windows, the Dock menu, the jayjay CLI launcher, and jayjay config for jj and Git diff and merge tool definitions.

See the full feature guide for screenshots and workflows.

Install

macOS

Requires macOS 26 or later.

brew install --cask hewigovens/tap/jayjay

Or download the latest .zip from GitHub Releases, unzip it, and move JayJay to Applications. JayJay updates itself through Sparkle; choose JayJay → Check for Updates to check now.

Beta builds: set the update channel to Beta in Settings → About, then check for updates. To install a beta directly, download its .zip from its pre-release page.

Linux

For x86_64 and aarch64. The installer picks the Debian package on apt-based systems and an AppImage elsewhere:

curl -fsSL https://jayjay.hewig.dev/install.sh | bash

Or download the AppImage from GitHub Releases. The guide covers the Arch pacman repo, betas, and .deb packages.

Windows

Install JayJay from the Microsoft Store and launch it from the Start menu. To try beta builds, download the Windows x64 portable ZIP from GitHub Releases, extract it, and run jayjay-gpui.exe; the portable ZIP has no automatic updater. Requires Windows 10 version 1903 or later, or Windows 11, with jj installed separately on PATH. Windows desktop behavior is still experimental.

Agent skill

The jayjay skill lets coding agents read and resolve your review notes, pre-mark straightforward files, and set JayJay up as jj's diff and merge tool. Install it with the skills CLI, or copy skills/jayjay into your agent's skills directory (such as ~/.claude/skills/jayjay):

npx skills add hewigovens/jayjay --skill jayjay

It needs the jayjay command on PATH: on macOS choose JayJay → Install Command Line Tool…; the Linux installer sets it up.

Feedback

Join the JayJay Discord community to ask questions, share workflows, and give feedback.

Found a bug or want a feature? Open an issue on GitHub.

Build the app

Follow Contributing to install prerequisites, then:

just run            # Build and launch the SwiftUI macOS app
just install-cli    # Install the jayjay launcher to ~/.local/bin
jayjay .            # Open the current repo
just gpui           # Build and launch the GPUI app
just gpui-appimage  # Build the Linux AppImage

Rust Libraries

The Rust workspace keeps diff rendering, review state, and shared domain types independent of jj-lib.

Crate	Role	jj-lib?
jj-diff	Standalone diff engine: histogram line diff, word diff, syntax highlighting, context collapse, side-by-side rows	No
jayjay-primitives	Shared jj-lib-free domain and review identity types	No
jayjay-review	Local review marks, notes, and reconciliation	No
jayjay-markdown	Safe Markdown-to-HTML renderer for rich previews	No
jayjay-network	Platform-neutral HTTP request handling with an optional blocking client	No
jayjay-core	App-facing repo operations, jj data access, mutations, and format projections	Yes
jayjay-uniffi	UniFFI bindings for the SwiftUI app and WASM consumers	Indirect
jayjay-cli	Thin app launcher; command-line subcommands are served by the bundled macOS app, or the GPUI app on Linux and Windows	No

Rule of thumb: jj-lib belongs in jayjay-core. Diff rendering, review state, and shared domain types stay below that boundary so they can be reused without embedding jj's repo model.

flowchart LR
  swiftui["SwiftUI app (macOS)"] --> uniffi[jayjay-uniffi]
  uniffi --> core["jayjay-core (jj-lib)"]
  gpui["GPUI app (Linux, Windows)"] --> core
  cli[jayjay-cli]

  subgraph portable [No jj-lib]
    review[jayjay-review]
    diff[jj-diff]
    primitives[jayjay-primitives]
    network[jayjay-network]
    markdown[jayjay-markdown]
  end

  core --> review
  core --> network
  review --> diff
  review --> primitives
  cli --> primitives
  uniffi --> markdown
  gpui --> markdown

  classDef app fill:#E3F2FD,stroke:#1E88E5,color:#0D47A1;
  classDef ffi fill:#E8F5E9,stroke:#43A047,color:#1B5E20;
  classDef core fill:#FFF8E1,stroke:#FB8C00,color:#E65100;
  classDef lib fill:#ECEFF1,stroke:#546E7A,color:#263238;
  class swiftui,gpui,cli app;
  class uniffi ffi;
  class core core;
  class review,diff,primitives,network,markdown lib;

Loading

Arrows point from a crate to the crates it depends on.

jj-diff

jj-diff is the standalone diff engine behind JayJay, available on crates.io. It has zero dependency on jj-lib.

[dependencies]
jj-diff = "0.1.1"

use jj_diff::{collapse_context_with_mapping, compute_file_diff};

let diff = compute_file_diff("main.rs", &old_content, &new_content, false);
let collapsed = collapse_context_with_mapping(&diff);

for line in &collapsed.diff.lines {
    // render line.style and line.spans in your UI
}

Features:

• Histogram line diff via similar.
• Word-level highlighting within changed lines.
• tree-sitter syntax highlighting for common source formats.
• Context collapsing with display-to-full line index mapping.
• Side-by-side row building for two-column renderers.
• Placeholder detection for Git LFS, submodules, and binary content.

See crates/jj-diff/README.md for the full API.

Docs

• User Guide - shipped features and workflows (docs/guide.html).
• Keyboard Shortcuts - every shortcut, grouped by area; Cmd+/ opens a quick reference in the app.
• Issues - planned work and known gaps.
• Contributing - setup, development checks, testing, and pull request policy.
• Agent instructions - repository constraints and focused engineering guides.
• DeepWiki - indexed codebase reference.
• FAQ - install, licensing, platform support, and common feature questions.
• Blog - notes on Jujutsu, collaboration, and the tools around them.

License

• Rust crates (crates/): Apache-2.0
• Apps and everything else (shell/, docs, packaging): BSL 1.1 - free to use, modify, and redistribute; paid app store distribution requires permission. Converts to Apache-2.0 on 2030-03-23.