1zero Browser
Tabless Electron browser: command-center tab cards, built-in ad blocker and AI, for Mac, Windows and Linux.
1zero Browser is a free Electron browser from a small team called 1zero. It has no tab strip or toolbar: tabs live in a command center of searchable cards with nested folders, pinned tabs and two-tab split view, opened by a shortcut or a pointer shake. Its site has a "Coming from Arc?" pitch and it imports Arc's history, sign-ins, open tabs and extensions, but it has no sidebar or Spaces and it does not import Arc's spaces or folders. It adds Peek, a small window for outside links, profiles, a Dynamic Island for media and timers, a built-in ad blocker, and an AI side chat. It runs on castlabs Electron 44.1.0 with Widevine, installs Chrome Web Store extensions through electron-chrome-extensions, and has no sync or mobile app. It is closed source and donation-funded; its FAQ says builds are not yet code-signed.
50% Arc feature parity (yes = 1, partial = ½).
AI optional
AI chat and agent in a side panel (your Claude Code, Codex, Gemini or Cursor, or paid 1zero AI); off until Settings → AI → Enabled is switched on.
1zero.appNot counted in Arc parity: some people want AI, some avoid it.
None found
No ads, wallet, feed or upsells; no analytics SDK. Update checks are counted server-side by a hashed ID. 1zero AI plans appear only in Settings → AI.
1zero.appAds, crypto, paid upsells, news feeds, default-on telemetry, required accounts.
Organization
| Feature | 1zero Browser | Arc | Note |
|---|---|---|---|
| Vertical sidebarTabs live in a vertical sidebar that is the main tab UI and can be hidden. | ✕ | ✓ | Tabs are a searchable card grid (command center), not a strip or vertical list. A side panel holds AI/sites.1zero.app |
| SpacesSeveral workspaces per window, each with its own pinned and open tabs, switched by swipe or shortcut. | ✕ | ✓ | No workspaces. Profiles are separate windows; tabs are organised with nested folders.1zero.app |
| 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. | ◐ | ✓ | Profiles have their own logins, history, tabs and extensions, but there are no Spaces to attach or share them.1zero.app |
| Global favoritesPinned icons at the top of the sidebar shared by every Space (Zen calls them Essentials). | ◐ | ✓ | Sidebar sites sit on a global rail, but they open in a side panel; pinned tabs are plain cards.1zero.app |
| Pinned tabs & foldersPer-space pinned tabs that act like bookmarks, with nested folders. | ◐ | ✓ | Pinned tabs and nested folders exist, but not per space (there are no spaces).1zero.app |
| Auto-archive tabsUnpinned tabs close automatically after a set time and stay recoverable in an archive. | ◐ | ✓ | Off by default; closes unvisited tabs after 2 h to 30 d with an Undo toast. No archive view.1zero.app |
| Space themesPer-space colour or gradient themes. | ◐ | ✓ | 13 palettes plus custom themes, one global theme; tabs and folders take colours. No per-space themes.1zero.app |
Browsing
| Feature | 1zero Browser | Arc | Note |
|---|---|---|---|
| Split ViewTwo or more tabs side by side in one window. | ◐ | ✓ | Drop a tab on another's edge for side by side; the app pairs two tabs at a time.1zero.app |
| Link previewOpen a link in an overlay without leaving the current page (Zen calls it Glance). | ✓ | ✓ | Long-press or Alt-click a link to open it over the page; keep it as a tab or in split view.1zero.app |
| Mini windowA small, chrome-less window for links opened from other apps or a quick search. | ✓ | ✓ | Links from other apps open in a small window over that app, on by default; Open keeps it as a tab.1zero.app |
| Command barA ⌘T palette that searches tabs, history, bookmarks and browser commands. | ✓ | ✓ | Tab dialog searches tabs, folders, history, downloads, closed tabs and notes, and runs commands.1zero.app |
| Link routingRules that send links from other apps to a chosen space or profile. | ◐ | ✓ | Per-site rules send links from other apps to a chosen folder; no rules for spaces or profiles.1zero.app |
| Site customizationPer-site custom CSS/JS, or zapping elements off a page. | ✕ | ✓ | No per-site CSS/JS or element zapping in the feature list or settings.1zero.app |
| Auto picture-in-picturePlaying video pops out into picture-in-picture automatically when you switch tabs. | ✓ | ✓ | A video playing with sound moves to a floating popup when you switch tabs.1zero.app |
Compatibility & migration
| Feature | 1zero Browser | Arc | Note |
|---|---|---|---|
| Arc importImports Arc spaces, pinned tabs and folders. | ◐ | – | Imports history, sign-ins, open tabs and extensions from Arc; no spaces, pinned tabs or folders.1zero.app |
| Chrome extensionsInstalls extensions from the Chrome Web Store. | ◐ | ✓ | Installs from the Chrome Web Store on Electron; missing chrome.* APIs are stubbed, so some extensions break.1zero.app |
| DRM (Widevine)Netflix, Disney+, Spotify web and other DRM video/audio play. Chromium forks need a Google Widevine licence. | ✓ | ✓ | Castlabs Electron build with Widevine; maker says Netflix and Prime Video play. Not played here.reddit.com |
| PasskeysWebAuthn passkeys, Touch ID and the system/iCloud keychain. | ? | ✓ | |
| SyncSpaces, pinned tabs and settings sync across devices. | ✕ | ✓ | No sync setting; the 1zero account is for 1zero AI and a shared theme.1zero.app |
| Mobile appiPhone, iPad or Android app that shares spaces with desktop. | ✕ | ◐ | Desktop app for macOS, Windows and Linux only.1zero.app |
Extras
| Feature | 1zero Browser | Arc | Note |
|---|---|---|---|
| Built-in ad blockerAd and tracker blocking without installing an extension. | ✓ | ✓ | Native ad, tracker and cookie-banner blocker, on from first launch (incognito too).1zero.app |
Extension support
Which extension formats and stores run, beyond the Chrome Web Store row above. Not counted in Arc parity.
| Feature | 1zero Browser | Arc | Note |
|---|---|---|---|
| Manifest V2 extensionsThe older extension format Chrome removed in 2025. Needed for full uBlock Origin and other extensions that block requests. | ? | ✕ | |
| Manifest V3 extensionsThe current extension format used by the Chrome Web Store (and supported by Firefox and Safari). | ◐ | ✓ | Installs from the Web Store, but Electron lists no declarativeNetRequest, so MV3 blockers cannot block.github.com |
| Firefox add-onsAdd-ons from addons.mozilla.org or .xpi files install and run. | ✕ | ✕ | Chrome Web Store only; the site says Firefox add-ons stay behind when importing.1zero.app |
| Safari extensionsSafari web extensions (the App Store extension apps Safari uses) install and run. | ✕ | ✕ | Chrome-format extensions only; Electron has no Safari extension host.github.com |