den
A fast, native macOS browser built on WebKit, where everything is a plugin.
[!IMPORTANT]
den is in early development. It browses the web with an Arc-style sidebar, spaces, split view and a command bar, but there's no sync yet. The first pre-release, 0.1.0-alpha.1, is out; see Getting started.
What is den?
den is an open-source browser for macOS 26 Tahoe and later, built on the WebKit engine that ships with the system. It takes the interface people love from Arc, the connected workflow from Dia, and the openness of Zen, and puts them in a browser that stays light and starts instantly.
It exists because the browsers with the best interfaces are heavy, closed, or no longer actively developed, and the lightweight ones don't feel good to use.
Principles
- Plugin-based. The core is a small host. Tabs, the sidebar, split view and connections are all plugins.
- Hot-swappable. Any plugin can be loaded, unloaded, updated or replaced while the browser runs, without losing your tabs.
- Lazy by default. Nothing loads until you need it: plugins, connections, web pages.
- Minimal footprint. Idle tabs should cost close to nothing. Memory and energy regressions are treated as bugs.
Planned features
- Arc-style interface: vertical sidebar tabs, spaces, split view, command bar, link previews
- Connections to Slack, GitHub and more, with a daily briefing that turns them into a todo list, and a personalized feed
- On-device AI via Apple Intelligence, used only for the briefing and feed. No chat, nothing sent to the cloud
- Chrome and Firefox extension support
- Native macOS integration: passkeys, Keychain, Shortcuts, iCloud sync
Much of this already works (below). What's still in progress is in Coming soon.
Roadmap and status
| # | Step | Status |
|---|
| 1 | Research Arc, Dia, Zen, WebKit, extension support, plugin design | ✅ |
| 2 | Feature and architecture design | 🟡 Thin-host migration planned, not started |
| 3 | Plugin host and app skeleton | ✅ |
| 4 | Core browsing: tabs, sidebar, spaces, profiles | 🟡 Tabs, sidebar, spaces, split view, Peek, Settings done; profiles work without a UI; downloads and windows queued |
| 5 | Extensions and content blocking | 🟡 Chrome/Firefox extensions and store installs done; built-in blocker queued |
| 6 | Connections, daily briefing, personalized feed | 🟡 Slack, GitHub, briefing and feed done (verified against local fakes); auto-connect and more connections queued |
| 7 | First public release | 🟡 Pre-release 0.1.0-alpha.1 with OTA updates; not notarized yet |
✅ shipped · 🟡 in progress or partly shipped · ⏳ queued. The full checklist is in ROADMAP.md. What's being built now is in Coming soon.
What works today
Each item is covered by swift test or a --scenario run of the real app. The user guide has the details, and Tips & hidden gems has everything you won't find by looking.
- Sidebar & tabs: favorites, pinned tabs that remember their page, nested folders, Today tabs that archive after 24 h, a searchable Library, ⌃Z undo, drag and drop (onto folders, spaces, the page, and a tab onto another for a split), a speaker to mute a tab, idle tabs discarded after 5 min in the background (their process exits; a snapshot on disk makes the restore instant)
- Spaces & themes: a theme per space, two-finger swipe, the space menu, footer drag-reorder, a separate profile (logins, cookies) per space
- Command bar: tabs in every space, the archive, URLs, web search, site keywords, every command, and settings you can flip right from the bar (⌘T / ⌘L)
- Peek, split view & Little Arc: ⇧-click any link to Peek, 2–4 panes by dragging a tab onto the page, an opt-in mini window for links from other apps
- Picture in picture: the Mac's own, the one Safari uses. Leave a playing video (another tab or space, a covered, hidden or minimized window) and it floats along on top of everything, on every Space; come back and it slides home. ⌥⌘P any time
- Hover previews: rest on a tab for its PR checks and reviews, next meeting, unread mail, or a snapshot
- Connections & briefing: Slack and GitHub through your own session in den, a morning briefing with todos, on-device summaries
- Extensions: Chrome Web Store and Firefox Add-ons ("Add to den"), popups, per-site access; uBlock Origin Lite, Dark Reader verified
- Privacy & passwords: dark mode for every website, Google sign-in, a Touch ID password vault in your Keychain
Build and run
Requires macOS 26, Xcode 26 (Swift 6.2+), and a Swift toolchain with the Embedded Swift stdlib for the plugins (from swift.org or swiftly). SwiftPM fetches the cordis-swift package. Step by step: Getting started.
scripts/run.sh --demo # build build/den.app, then launch it with demo spaces and tabs
scripts/bundle.sh # only build and sign build/den.app
scripts/make-signing-identity.sh # once: stable local signing identity (Keychain/TCC survive rebuilds)
scripts/test.sh # swift test (host and plugin tests), one run at a time machine-wide
scripts/snapshots.sh # regenerate docs/screenshots
scripts/measure-memory.sh main # memory of den + its WebKit processes
Useful flags: --demo, --appearance light|dark, --scenario <name>, --snapshot out.png, --measure-launch, --no-den-home, --background (automation: no Dock icon, no focus, windows off-display). Scenarios need a build with the Scenarios trait (swift build, or DEN_SCENARIOS=1 scripts/bundle.sh).
scripts/install.sh # verified build (bundle + swift test) -> /Applications/den.app -> relaunch with your tabs
scripts/dev-sync.sh # keep the installed den on the latest code: plugins hot-swap, host changes reinstall
Updates: release channels (Sparkle for the app, signed hot-swapped plugins) or, for developers, scripts/updater.sh install to follow main. See docs/updates.md.
Extend den from ~/.den: drop in plugins (prebuilt .dylib or a folder of .swift files den compiles), themes and config.toml. Changes apply live. See docs/den-home.md.
The host API that plugins code against is in docs/host-api.md.
Let your AI agent do it: the den skill teaches Claude Code, Codex and other agents to edit ~/.den, write plugins and read den's logs. Install it with bunx skills add abhishakenp/den --skill den -g.
The homepage source is in website/ (Next.js, deployed on Vercel).
Design docs
Contributing
den is early, and design feedback is the most useful contribution right now. Open an issue to discuss an idea or challenge a decision. To build and test on GitHub Actions instead of your Mac, see remote build mode.
License
MIT
