Yab

SigmaOS vs Opera

We make Yab, the third column.facts checked Oct 9 ↓

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.

Opera One is Opera’s free Chromium browser on every desktop and phone, with a free browser VPN, an ad blocker, messengers in the sidebar and Opera AI. Its agents are in a separate browser, Opera Neon.

The short answer

Pick SigmaOS
  • 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
Pick Opera
  • if you want a free browser VPN and an ad blocker built in
  • if you keep WhatsApp, Telegram or Slack open in a sidebar
  • if you sort work into workspaces, Tab Islands and split screen
Or Yabours
  • 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

SigmaOS and Opera, with Yab beside them for a Mac.

SigmaOS vs Opera
WhatSigmaOSOperaYab
Made bySigmaOS Inc. (London)OperaSerafim Korablev
StatusNo release notes since February 2025UpdatedUpdated
Runs onMacMac, Windows, Linux, iPhone and AndroidMac
Phone appNone; Mac only. iOS has been on its roadmap since 2021iPhone, iPad and Android; syncs tabs, bookmarks and Speed Dials with an Opera accountNot yet
PriceFree; Personal Pro $20/month or Personal Max $30/month for more AIFree, with Opera AI and a browser VPN; VPN Pro is paidFree; its AI runs on your own Claude or ChatGPT plan
AIChat about pages, on its own AI serviceChat about pages, on its own AI serviceAn agent that works in pages, on your Claude or ChatGPT plan
Driven by outside agentsNoMCPMCP and a command line
EngineWebKitChromiumWebKit
Tabs down the sideYesA settingYes
SpacesYesYesYes
Split ViewYesYesYes
ExtensionsChrome Web StoreChrome Web StoreChrome Web Store
Ad blockerBuilt inBuilt inBuilt in
Open sourceNoNoNo

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.

AIa matter of taste

Both have AI to ask about pages, and neither does the clicking for you. Airis chats about the page you are on, sums it up, looks things up and translates; no agent. Opera AI answers about the page, Tab Islands, videos and files, and makes images, with no account; it doesn’t click or fill forms.

Agents like Claude Code and CodexOpera leads

SigmaOS has no MCP server or command line for outside agents. Opera can be driven over MCP, through Browser Connector, in early testing, which lets ChatGPT or Claude read and open tabs but not click or type.

Tabs and windowseven

SigmaOS has tabs down the side, spaces and Split View. Opera has tabs down the side as a setting, spaces, Split View, folders in the sidebar and tabs that sleep.

PriceOpera leads

SigmaOS: Free; Personal Pro $20/month or Personal Max $30/month for more AI. Opera: Free, with Opera AI and a browser VPN; VPN Pro is paid.

Where it runsOpera leads

SigmaOS runs on Mac. Opera runs on Mac, Windows, Linux, iPhone and Android. On a Mac, SigmaOS needs macOS 12 or later. SigmaOS has no phone app: Mac only. iOS has been on its roadmap since 2021. On the phone, Opera: iPhone, iPad and Android; syncs tabs, bookmarks and Speed Dials with an Opera account.

Engine and extensionsa matter of taste

SigmaOS is built on WebKit, the engine Safari uses; Opera on Chromium, as Chrome is. Both take extensions from the Chrome Web Store.

PrivacyOpera leads

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. Opera has an ad blocker built in and a VPN. Opera AI sends only the current page or Tab Island when you write with page access on; Opera says it doesn’t send your history.

UpdatesOpera leads

SigmaOS: Still downloadable, with no public release notes since version 1.19 in February 2025. Opera is updated as usual.

What their pages don’t lead with

Real limits, from the makers’ own words and our own use.

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

Opera

  • Opera AI only chats and sums up; agents need Opera Neon at $19.90 a month
  • The free VPN covers the browser only, with three locations
  • The ad blocker is off until you turn it on
  • Browser Connector is in early testing and needs an Opera account

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

  • July 23, 2026Opera: Vertical tabs shipped to all Opera One users
  • April 16, 2026Opera: Browser Connector lets ChatGPT and Claude read your tabs over MCP (Early Bird)
  • December 11, 2025Opera: Opera AI replaced Aria in Opera One, GX and Air
  • February 4, 2025SigmaOS: Version 1.19.0, a performance update, the last release with public notes

Questions

Is SigmaOS free?

Yes, with limits on its AI. Free; Personal Pro $20/month or Personal Max $30/month for more AI.

Is Opera free?

Yes. Free, with Opera AI and a browser VPN; VPN Pro is paid.

Which has an AI agent, SigmaOS or Opera?

Neither has an agent that does tasks in your pages. Airis chats about the page you are on, sums it up, looks things up and translates; no agent. Opera AI answers about the page, Tab Islands, videos and files, and makes images, with no account; it doesn’t click or fill forms.

Which runs on Windows, SigmaOS or Opera?

Opera does. SigmaOS runs on Mac.

Do SigmaOS and Opera have phone apps?

Opera does. SigmaOS has no phone app: Mac only. iOS has been on its roadmap since 2021. On the phone, Opera: iPhone, iPad and Android; syncs tabs, bookmarks and Speed Dials with an Opera account.

Can I move from Opera to SigmaOS?

Yes: SigmaOS’s own help says it brings in from Opera.

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 SigmaOS; an agent that works in your signed-in tabs, 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

SigmaOS vs ArcSigmaOS vs VivaldiSigmaOS vs ZenSigmaOS vs OrionSigmaOS vs ChromeSigmaOS vs SafariSigmaOS vs EdgeSigmaOS alternativesYab vs SigmaOSOpera vs ChromeOpera vs SafariOpera vs EdgeOpera vs FirefoxOpera vs BraveArc vs OperaDia vs OperaOpera alternativesYab vs Opera
Sources, read October 9, 2026. Something out of date? Write to hello@serafimlabs.io and we fix it.

Yab, Yet Another Browser.

Free for the Mac. Arc’s sidebar, your own Claude or ChatGPT as the agent, Chrome extensions on WebKit.

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