Orbit

An open-source, Chromium-based browser built around a vertical sidebar: Spaces with their own colours, pinned tabs and Favorites that always return to their page, Today tabs that tidy themselves away into an Archive, folders, Split View, a command bar, link previews and a mini window for links from other apps. It's written in TypeScript on Electron, so every tab is real Chromium with Chromium DevTools and Chrome extensions.

Status: pre-alpha. The core experience is being built now. FEATURES.md is the feature checklist: every behaviour in the spec, and whether it is built, tested and feels right.

Clean room

Orbit is an independent, clean-room implementation in the spirit of Arc. It was built from a behaviour specification written in our own words from public documentation and observed behaviour, never from another browser's code, binaries or assets. Its name, icon and interface text are original. Orbit is not affiliated with, endorsed by or connected to The Browser Company or Atlassian.

Develop

Requirements: Node.js 22+ and npm. macOS is the primary target. Linux works for development and testing.

npm ci
npm run dev          # run with hot reload
npm run build        # production build into out/
npm start            # run the production build

Checks:

npm run typecheck
npm run lint
npm test             # unit tests (vitest)
npm run test:e2e     # end-to-end tests (Playwright for Electron); run `npm run build` first

Before a merge, the whole check runs locally on the PR's head (docs/ARCHITECTURE.md §9). Its e2e run uses one worker, no retries and a 1440×900 screen; on Linux without a display:

xvfb-run -a -s "-screen 0 1440x900x24" npx playwright test --workers 1 --retries 0

Performance and screen captures (see docs/ARCHITECTURE.md §8–9):

npm run perf                      # cold start, tab/Space switch, command bar, scroll, memory vs Chromium
ORBIT_FFMPEG=/path/to/ffmpeg npm run capture -- <scenario>   # needs an ffmpeg with x11grab

Packaging (unsigned):

npm run package:mac      # .dmg and .zip (arm64 + x64) in release/
npm run package:linux    # unpacked Linux build in release/

Build the macOS .dmg/.zip on a Mac. The CI workflow that built them (on pushes to main, on manual runs and for PRs labelled package) is turned off.

How it's built

• Main process owns all state (one store, broadcast to the UI as small patches), every tab's WebContentsView, sessions (one per profile), windows, shortcuts and persistence.
• UI is React 19 in sandboxed renderers: the sidebar shell, plus a transparent overlay for the command bar, link previews and menus.
• Tabs sleep when idle and wake on demand, so a sidebar with hundreds of tabs stays light.

The full map, file ownership and performance budgets are in docs/ARCHITECTURE.md.

License

MIT. See LICENSE.