YabSigmaOS vs Orion
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.
Orion is Kagi’s browser for Mac, iPhone and iPad, on WebKit, the engine Safari uses, that also runs many Chrome and Firefox extensions. It has no telemetry and blocks ads by default.
The short answer
- 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 want Safari’s engine with Chrome and Firefox extensions, on Mac and iPhone
- if you want ads blocked and no telemetry from the start
- if you pay for Kagi Search
- 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
At a glance
SigmaOS and Orion, with Yab beside them for a Mac.
| What | SigmaOS | Orion | Yab |
|---|---|---|---|
| Made by | SigmaOS Inc. (London) | Kagi | Serafim Korablev |
| Status | No release notes since February 2025 | Updated | Updated |
| Runs on | Mac | Mac and iPhone | Mac |
| Phone app | None; Mac only. iOS has been on its roadmap since 2021 | iPhone and iPad; syncs tabs, bookmarks and passwords with your Mac through iCloud | Not yet |
| Price | Free; Personal Pro $20/month or Personal Max $30/month for more AI | Free; Orion+ supporter plan $5/month, $50/year or $150 once | Free; its AI runs on your own Claude or ChatGPT plan |
| AI | Chat about pages, on its own AI service | Chat about pages, on its own AI service | An agent that works in pages, on your Claude or ChatGPT plan |
| Driven by outside agents | No | No | MCP and a command line |
| Engine | WebKit | WebKit | WebKit |
| Tabs down the side | Yes | A setting | Yes |
| Spaces | Yes | Yes | Yes |
| Split View | Yes | No | Yes |
| Extensions | Chrome Web Store | Chrome and Firefox stores | Chrome Web Store |
| Ad blocker | Built in | Built in | Built in |
| Open source | No | 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.
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. Orion sums up pages and videos through Kagi’s Summarizer, with a paid Kagi plan; no chat and no agent.
Tabs and windowsSigmaOS leads
SigmaOS has tabs down the side, spaces and Split View. Orion has tabs down the side as a setting, spaces, folders in the sidebar and tabs that sleep.
PriceSigmaOS leads
SigmaOS: Free; Personal Pro $20/month or Personal Max $30/month for more AI. Orion: Free; Orion+ supporter plan $5/month, $50/year or $150 once.
Where it runsOrion leads
SigmaOS runs on Mac. Orion runs on Mac and iPhone. On a Mac, SigmaOS needs macOS 12 or later and Orion needs macOS 10.14 or later. SigmaOS has no phone app: Mac only. iOS has been on its roadmap since 2021. On the phone, Orion: iPhone and iPad; syncs tabs, bookmarks and passwords with your Mac through iCloud.
Engine and extensionsa matter of taste
Both are built on WebKit, the engine Safari uses. SigmaOS takes extensions from the Chrome Web Store, Orion from both Chrome’s and Firefox’s stores.
Privacyeven
Both have 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. Orion has no telemetry, Kagi says; page summaries and translations go to Kagi’s servers.
UpdatesOrion leads
SigmaOS: Still downloadable, with no public release notes since version 1.19 in February 2025. Orion 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
Orion
- Apple only: the Windows and Linux versions stopped on October 2, 2026
- Not every extension works: support is partial
- No Split View of two tabs
- Closed source, and page summaries need a paid Kagi plan
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 2, 2026Orion: Kagi ended Orion for Linux and Windows to focus on Mac and iOS
- June 23, 2026Orion: Orion 1.1 added per-tab containers and page translation
- November 25, 2025Orion: Orion 1.0 for Mac left beta
- 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 Orion free?
The browser is; its AI isn’t. Free; Orion+ supporter plan $5/month, $50/year or $150 once.
Which has an AI agent, SigmaOS or Orion?
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. Orion sums up pages and videos through Kagi’s Summarizer, with a paid Kagi plan; no chat and no agent.
Which runs on Windows, SigmaOS or Orion?
Neither. SigmaOS runs on Mac; Orion on Mac and iPhone.
Do SigmaOS and Orion have phone apps?
Orion does. SigmaOS has no phone app: Mac only. iOS has been on its roadmap since 2021. On the phone, Orion: iPhone and iPad; syncs tabs, bookmarks and passwords with your Mac through iCloud.
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 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
- Orion home page
- Kagi blog: Orion 1.0, 2025-11-25
- Kagi blog: An update on Orion for Linux and Windows, 2026-10-02
- Orion+ help page ($5/month, $50/year, $150 lifetime)
- Orion macOS release notes (1.1.3, 2026-09-28)
- Orion supported OS versions
- Orion update feed for macOS 10.14 (1.1.3, minimum 10.14.4)
- Orion Summarize Page
- Orion importing data
- Orion vertical tabs
- Orion tab groups
- Orion password management
- Orion ad and tracking blocking
- Orion respecting privacy (no telemetry)
- Orion Low Power Mode (suspends unused tabs)
- Orion FAQ (extensions, open source)
- Orion technical information (Web Extensions API support)
- Orion on the App Store (1.5.5)
- Orion feedback: split view request
- Kagi Help: Syncing Orion Data (tabs, bookmarks, reading list)
- Kagi Help: Troubleshooting syncing (iCloud Drive)
- Orion iOS/iPadOS release notes
- PiunikaWeb: Kagi says Orion for Android is ’not planned yet’ (2026-06-30)
- 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.