YabBrowserOS vs SigmaOS
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.
SigmaOS is a Mac browser on WebKit that treats tabs like a to-do list, in workspaces down the side, with an AI assistant called Airis.
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 workspaces and tabs you mark done, on a Mac
- if you browse by keyboard, with single-key shortcuts
- if you prefer WebKit to Chromium and want spaces
- 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 SigmaOS, with Yab beside them for a Mac.
| What | BrowserOS | SigmaOS | Yab |
|---|---|---|---|
| Made by | Felafax, Inc. | SigmaOS Inc. (London) | Serafim Korablev |
| Status | Updated | No release notes since February 2025 | Updated |
| Runs on | Mac, Windows and Linux | Mac | Mac |
| Phone app | None; desktop only, and no Android plans as of May 2026 | None; Mac only. iOS has been on its roadmap since 2021 | Not yet |
| Price | Free and open source; you pay your own AI provider | Free; Personal Pro $20/month or Personal Max $30/month for more AI | Free; its AI runs on your own Claude or ChatGPT plan |
| AI | An agent that works in pages, on its own AI or yours | Chat about pages, on its own AI service | 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 | WebKit | WebKit |
| Tabs down the side | Yes | Yes | Yes |
| Spaces | No | Yes | Yes |
| Split View | Yes | Yes | Yes |
| Extensions | Chrome Web Store | Chrome Web Store | Chrome Web Store |
| Ad blocker | No | Built in | Built in |
| Open source | Yes | No | 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. Airis chats about the page you are on, sums it up, looks things up and translates; no agent.
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. SigmaOS has no MCP server or command line for outside agents.
Tabs and windowseven
BrowserOS has tabs down the side, Split View and folders in the sidebar. SigmaOS has tabs down the side, spaces and Split View.
PriceBrowserOS leads
BrowserOS: Free and open source; you pay your own AI provider. SigmaOS: Free; Personal Pro $20/month or Personal Max $30/month for more AI.
Where it runsBrowserOS leads
BrowserOS runs on Mac, Windows and Linux. SigmaOS runs on Mac. On a Mac, SigmaOS needs macOS 12 or later. BrowserOS has no phone app: desktop only, and no Android plans as of May 2026. SigmaOS has no phone app: Mac only. iOS has been on its roadmap since 2021.
Engine and extensionsa matter of taste
BrowserOS is built on Chromium, as Chrome is; SigmaOS on WebKit, the engine Safari uses. Both take extensions from the Chrome Web Store.
Privacyeven
BrowserOS has 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. SigmaOS has an ad blocker built in. SigmaOS keeps history and cookies on your Mac unless you turn on sync, stored encrypted on AWS; its privacy policy doesn’t say where Airis requests go.
UpdatesBrowserOS leads
BrowserOS is updated as usual. SigmaOS: Still downloadable, with no public release notes since version 1.19 in February 2025.
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
SigmaOS
- Mac only
- No public release notes since version 1.19 in February 2025
- Chrome extensions only partly work, behind its WebKit+ option
- Its AI is an assistant, and regular use needs the $20 or $30 plans
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)
- 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 4, 2025SigmaOS: Version 1.19.0, a performance update, the last release with public notes
Questions
Is BrowserOS free?
Yes. Free and open source; you pay your own AI provider.
Is SigmaOS free?
Yes, with limits on its AI. Free; Personal Pro $20/month or Personal Max $30/month for more AI.
Which has an AI agent, BrowserOS or SigmaOS?
BrowserOS. BrowserOS’s agent, in the new tab and side panel, clicks, types, fills forms and pulls out data, on the AI you connect. Airis chats about the page you are on, sums it up, looks things up and translates; no agent.
Which runs on Windows, BrowserOS or SigmaOS?
BrowserOS does. SigmaOS runs on Mac.
Do BrowserOS and SigmaOS have phone apps?
BrowserOS has no phone app: desktop only, and no Android plans as of May 2026. SigmaOS has no phone app: Mac only. iOS has been on its roadmap since 2021.
Is SigmaOS still being updated?
Still downloadable, with no public release notes since version 1.19 in February 2025.
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
- SigmaOS home page
- SigmaOS upgrade (plans)
- SigmaOS download (macOS only)
- SigmaOS update feed (appcast)
- SigmaOS 1.19.0 update notes
- SigmaOS 1.17.0 update notes (password manager)
- SigmaOS common questions
- SigmaOS docs: ad blockers and WebKit+
- SigmaOS docs: migrating from Arc
- SigmaOS privacy policy
- TechCrunch: SigmaOS turns to AI features for monetization (2024-03-26)
- Launch HN (Aug 16, 2021): founder says iOS and iPadOS are on the roadmap
- 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.