Phi
Chromium browser with an Arc-style sidebar, Spaces over Profiles, URL Rules and a built-in AI assistant.
Phi is a Chromium-based browser from Phinomenon Inc. with a native macOS client written in Swift (AppKit and SwiftUI). It keeps a vertical sidebar, Spaces layered over Profiles, Split View, Peek and URL Rules, and it can migrate Arc Profiles and Spaces directly from the Mac. AI features (assistant, local Memory, background tasks) are on by default after sign-in and can be switched off. The macOS and Windows clients are Apache-2.0 on GitHub, while the Chromium engine build ships as a proprietary binary; Windows is an early-access build.
76% Arc feature parity (yes = 1, partial = ½).
Built-in AI
AI on by default
Assistant, Memory and agent tasks are on out of the box after sign-in; one switch in Settings turns all AI off. Skipping sign-in gives a plain browser.
phibrowser.comNot counted in Arc parity: some people want AI, some avoid it.
Bloat check
1 thing you didn't ask for
- Telemetry on by defaultAnonymous PostHog counts have no off switch. Usage stats and Sentry crash reports are opt-out: the onboarding box is pre-ticked outside Europe.github.com
No ads, wallet, feed or upsells found. Account is optional ('Explore without signing in'). Help page says stats are off by default; FAQ and code say on.
Ads, crypto, paid upsells, news feeds, default-on telemetry, required accounts.
Organization
| Feature | Phi | Arc | Note |
|---|---|---|---|
| Vertical sidebarTabs live in a vertical sidebar that is the main tab UI and can be hidden. | ✓ | ✓ | Sidebar is the main UI; Comfortable layout mode moves tabs back to a top strip.phibrowser.com |
| SpacesSeveral workspaces per window, each with its own pinned and open tabs, switched by swipe or shortcut. | ✓ | ✓ | Spaces have own bookmarks, theme and icon; pinned-tab scope is configurable.phibrowser.com |
| Profiles per Space (shareable)Each Space can use its own browser profile (separate cookies, logins, history), and one profile can be shared by several Spaces. | ✓ | ✓ | Each Space belongs to one Profile; one Profile can back several Spaces; new Profile can be created per Space.github.com |
| Global favoritesPinned icons at the top of the sidebar shared by every Space (Zen calls them Essentials). | ✓ | ✓ | Pinned tab scope "App" shares them across all Spaces and Profiles; default scope is Profile.phibrowser.com |
| Pinned tabs & foldersPer-space pinned tabs that act like bookmarks, with nested folders. | ◐ | ✓ | Pinned tabs are a flat grid; folders exist for per-Space bookmarks that open in place.github.com |
| Auto-archive tabsUnpinned tabs close automatically after a set time and stay recoverable in an archive. | ✕ | ✓ | Only manual Clear All Tabs; auto-close of idle tabs is an open feature request (#255).github.com |
| Space themesPer-space colour or gradient themes. | ✓ | ✓ | Each Space can have its own colour theme or follow the global one.phibrowser.com |
Browsing
| Feature | Phi | Arc | Note |
|---|---|---|---|
| Split ViewTwo or more tabs side by side in one window. | ◐ | ✓ | Two-pane Split View only; can be pinned or bookmarked as one item.phibrowser.com |
| Link previewOpen a link in an overlay without leaving the current page (Zen calls it Glance). | ✓ | ✓ | Peek View floating panel; automatic for cross-site links from pinned tabs/bookmarks, else Shift-click.phibrowser.com |
| Mini windowA small, chrome-less window for links opened from other apps or a quick search. | ✓ | ✓ | Kiosk window; external links open there via a Settings toggle.phibrowser.com |
| Command barA ⌘T palette that searches tabs, history, bookmarks and browser commands. | ◐ | ✓ | Cmd+T opens a new tab only; searching open tabs is a separate shortcut (Cmd+Shift+A).github.com |
| Link routingRules that send links from other apps to a chosen space or profile. | ✓ | ✓ | URL Rules by domain/URL send links to a Space, Incognito or Kiosk, or ask each time.github.com |
| Site customizationPer-site custom CSS/JS, or zapping elements off a page. | ✕ | ✓ | Bundle 2.16.1: no Boosts, zap or per-site CSS/JS strings in UI resources; extensions only.ota.phibrowser.com |
| Auto picture-in-picturePlaying video pops out into picture-in-picture automatically when you switch tabs. | ✓ | ✓ | Auto picture-in-picture: Off, Normal (default; on tab or app switch) or Park at edge.github.com |
Compatibility & migration
| Feature | Phi | Arc | Note |
|---|---|---|---|
| Arc importImports Arc spaces, pinned tabs and folders. | ✓ | – | Parses Arc StorableSidebar.json (Spaces, pins); history, cookies, extensions copied; no passwords import type.github.com |
| Chrome extensionsInstalls extensions from the Chrome Web Store. | ✓ | ✓ | Installs from the Chrome Web Store; extensions are per Profile.phibrowser.com |
| DRM (Widevine)Netflix, Disney+, Spotify web and other DRM video/audio play. Chromium forks need a Google Widevine licence. | ✓ | ✓ | Bundle 2.16.1: CDM helper + Widevine component updater, no bundled WidevineCdm; Netflix named in 2.13.0 notes.ota.phibrowser.com |
| PasskeysWebAuthn passkeys, Touch ID and the system/iCloud keychain. | ✓ | ✓ | Bundle 2.16.1: web-browser.public-key-credential entitlement; iCloud Keychain passkey code in Chromium 156.ota.phibrowser.com |
| SyncSpaces, pinned tabs and settings sync across devices. | ✓ | ✓ | Spaces, Profiles, bookmarks, pinned tabs, URL Rules, settings, history between Macs; labelled experimental.phibrowser.com |
| Mobile appiPhone, iPad or Android app that shares spaces with desktop. | ✕ | ◐ | No mobile app; Phi Link reaches the assistant through your own Telegram bot only.phibrowser.com |
Extras
| Feature | Phi | Arc | Note |
|---|---|---|---|
| Built-in ad blockerAd and tracker blocking without installing an extension. | ◐ | ✓ | Ads, trackers and cookie banners can be blocked per Profile, but all three switches are off by default.phibrowser.com |
Extension support
Which extension formats and stores run, beyond the Chrome Web Store row above. Not counted in Arc parity.
| Feature | Phi | Arc | Note |
|---|---|---|---|
| Manifest V2 extensionsThe older extension format Chrome removed in 2025. Needed for full uBlock Origin and other extensions that block requests. | ✕ | ✕ | Chromium 156 blocks MV2 with no flag; bundle holds stock MV2 handler strings, no restore patch found.chromium.googlesource.com |
| Manifest V3 extensionsThe current extension format used by the Chrome Web Store (and supported by Firefox and Safari). | ✓ | ✓ | Chromium 156 loads MV3 (max supported 3); Phi installs Chrome Web Store extensions per Profile.chromium.googlesource.com |
| Firefox add-onsAdd-ons from addons.mozilla.org or .xpi files install and run. | ✕ | ✕ | Chromium-based: Firefox .xpi add-ons are not CRX packages, so its installer rejects them.chromium.googlesource.com |
| Safari extensionsSafari web extensions (the App Store extension apps Safari uses) install and run. | ✕ | ✕ | Safari extensions are app extensions that only Safari loads; Chromium 156 has no loader for them.developer.apple.com |