YabBrowserOS vs Zen
BrowserOS is an open-source Chromium agent browser for Mac, Windows and Linux. Its agent runs on the AI you connect: an API key, a ChatGPT or Copilot plan, Claude Code or Codex, or a local model.
Zen is a free, open-source browser built on Firefox that brings Arc’s layout, tabs down the side with spaces, folders and Split View, to Mac, Windows and Linux.
The short answer
- if you want an open-source agent browser on your own AI keys or local models
- if you want Claude Code, Codex or Cursor to drive a signed-in browser over MCP
- if you use Linux
- if you want Arc’s layout, free and open source
- if you prefer Firefox’s engine and its add-ons
- if you want no AI in your browser at all
- if you miss Arc and want spaces, pins and folders kept, on a Mac
- if you already pay for Claude or ChatGPT and want it to work in your signed-in tabs
- if you want Claude Code, Codex or Cursor to drive a real browser over MCP
At a glance
BrowserOS and Zen, with Yab beside them for a Mac.
| What | BrowserOS | Zen Browser | Yab |
|---|---|---|---|
| Made by | Felafax, Inc. | Zen Browser team (open-source community project) | Serafim Korablev |
| Status | Updated | Updated | Updated |
| Runs on | Mac, Windows and Linux | Mac, Windows and Linux | Mac |
| Phone app | None; desktop only, and no Android plans as of May 2026 | None; Zen says it has no plans for a mobile version | Not yet |
| Price | Free and open source; you pay your own AI provider | Free and open source | Free; its AI runs on your own Claude or ChatGPT plan |
| AI | An agent that works in pages, on its own AI or yours | No AI | An agent that works in pages, on your Claude or ChatGPT plan |
| Driven by outside agents | MCP and a command line | No | MCP and a command line |
| Engine | Chromium | Gecko | WebKit |
| Tabs down the side | Yes | Yes | Yes |
| Spaces | No | Yes | Yes |
| Split View | Yes | Yes | Yes |
| Extensions | Chrome Web Store | Firefox add-ons | Chrome Web Store |
| Ad blocker | No | No | Built in |
| Open source | Yes | Yes | No |
Checked October 9, 2026 on each maker’s own pages, linked under Sources. Prices are per month, in US dollars.
Where they differ
What separates them, area by area. Where one plainly has more, it says who; where it comes down to taste, it says so.
AIBrowserOS leads
Only BrowserOS has an agent that clicks, types and finishes tasks in your pages. BrowserOS’s agent, in the new tab and side panel, clicks, types, fills forms and pulls out data, on the AI you connect. Zen has no AI: Firefox’s AI features are switched off by default.
Agents like Claude Code and CodexBrowserOS leads
BrowserOS can be driven over MCP and a command line, through a built-in MCP server with one-click setup for Claude Code, Codex and Cursor, and a command line. Zen has no MCP server or command line for outside agents.
Tabs and windowsZen leads
BrowserOS has tabs down the side, Split View and folders in the sidebar. Zen has tabs down the side, spaces, Split View, folders in the sidebar and tabs that sleep.
PriceBrowserOS leads
BrowserOS: Free and open source; you pay your own AI provider. Zen: Free and open source.
Where it runseven
Both run on Mac, Windows and Linux. On a Mac, Zen needs macOS 10.15 or later. BrowserOS has no phone app: desktop only, and no Android plans as of May 2026. Zen has no phone app: Zen says it has no plans for a mobile version.
Engine and extensionsa matter of taste
BrowserOS is built on Chromium, as Chrome is; Zen on Gecko, Firefox’s engine. BrowserOS takes extensions from the Chrome Web Store, Zen from Firefox’s add-ons.
Privacyeven
Both have open code. BrowserOS sends prompts and pages only to the AI you connect, or keeps them local with Ollama or LM Studio; it sends anonymous usage analytics. Zen sends no telemetry or crash reports, by its privacy policy; optional sync keeps encrypted data on Mozilla’s servers.
What their pages don’t lead with
Real limits, from the makers’ own words and our own use.
BrowserOS
- No built-in model since version 0.51: connect a provider before the agent works
- Its own docs say local models are too weak for agent tasks
- Before 1.0 and changing fast: Skills and Memory were pulled in June 2026
- No phone apps
Zen Browser
- Releases are still labeled beta
- No phone app, and none planned
- Firefox add-ons only, not the Chrome Web Store
- No ad blocker of its own beyond Firefox’s tracking protection
Yab, honestly
- Mac only: macOS 15.4 or later, no Windows, iPhone or Android
- New: first released in September 2026
- Its AI needs a Claude or ChatGPT plan; ChatGPT’s free plan may work with low limits
- WebKit, as in Safari: a site tested only in Chrome can misbehave
- Closed source
What changed lately
- October 5, 2026BrowserOS: Built-in model and account sign-in removed; Chromium 155 (0.51.0)
- September 5, 2026Zen: Spaces, folders and tabs sync between devices with a Mozilla account (1.22b)
- June 17, 2026BrowserOS: Claude Code and Codex built into the agent; Skills and Memory removed (0.46.0)
- March 9, 2026BrowserOS: Vertical tabs became the default (0.42.0)
- February 28, 2026Zen: Live folders for GitHub issues, pull requests and RSS (1.19b)
- August 27, 2025Zen: Tab folders added (1.15b)
Questions
Is BrowserOS free?
Yes. Free and open source; you pay your own AI provider.
Is Zen Browser free?
Yes. Free and open source.
Which has an AI agent, BrowserOS or Zen?
BrowserOS. BrowserOS’s agent, in the new tab and side panel, clicks, types, fills forms and pulls out data, on the AI you connect. Zen has no AI: Firefox’s AI features are switched off by default.
Do BrowserOS and Zen run on Windows?
Yes, both. BrowserOS runs on Mac, Windows and Linux; Zen on Mac, Windows and Linux.
Do BrowserOS and Zen have phone apps?
BrowserOS has no phone app: desktop only, and no Android plans as of May 2026. Zen has no phone app: Zen says it has no plans for a mobile version.
Is there a third option on a Mac?
Yab, Yet Another Browser, is free for the Mac: tabs down the side with spaces, folders and Split View, as in BrowserOS; an agent in your signed-in tabs like BrowserOS’s, on the Claude or ChatGPT plan you already pay for. Claude Code, Codex and any MCP client can drive it too. It runs on WebKit, the engine Safari uses, and takes Chrome extensions. It is Mac only, and new.
More comparisons
- BrowserOS GitHub repo (README)
- BrowserOS README (browser for humans)
- BrowserOS v0.51.0 release notes
- BrowserOS changelog
- BrowserOS docs: vertical tabs
- BrowserOS docs: ad blocking
- BrowserOS docs: getting started
- BrowserOS docs: MCP clients
- BrowserOS site FAQ
- BrowserOS privacy policy (updated 2026-03-13)
- BrowserOS site: macOS, Windows, Linux
- GitHub issue #1030 (May 25, 2026): maintainer says no plans to add Android support
- BrowserOS docs, Sync to Cloud: chats, model settings, schedules and profile sync between desktops
- Zen home page
- Zen download page (macOS universal, Windows, Linux; beta)
- Zen 1.23.2b release (macOS universal dmg; Info.plist minimum 10.15)
- Zen 1.23.1b release (Firefox 157.0.1)
- Zen license (MPL-2.0)
- Zen AI preferences (all off)
- Zen welcome flow (Firefox import wizard)
- Firefox import from another browser
- Zen 1.15b release (folders)
- Zen 1.19b release (live folders)
- Zen 1.22b release (sync)
- Zen 1.12.9b release (tab unloader uses Firefox tab discarding)
- Zen FAQ (no mobile plans, donations)
- Zen Workspaces
- Zen Split View
- Zen Extensions (addons.mozilla.org)
- Zen Privacy and Security (Firefox password manager, tracking protection)
- Zen privacy policy
- Firefox 157 system requirements
- Yab Manual: Bringing in from another browser
- Yab Manual: Connecting Claude or ChatGPT
- Yab Manual: Extensions
- Yab Manual: Yab’s tools over MCP
- Yab Manual: Privacy
Yab, Yet Another Browser.
Free for the Mac. Arc’s sidebar, your own Claude or ChatGPT as the agent, Chrome extensions on WebKit.