YabSigmaOS vs Comet
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.
Comet is Perplexity’s free Chromium browser for Mac, Windows, iPhone and Android, with Perplexity’s search and an assistant that can act on pages for you.
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 use Perplexity and want its search and agent in the browser
- if you want one AI browser on Mac, Windows, iPhone and Android
- if you want a free Chromium browser with an ad blocker built in
- 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 Comet, with Yab beside them for a Mac.
| What | SigmaOS | Perplexity Comet | Yab |
|---|---|---|---|
| Made by | SigmaOS Inc. (London) | Perplexity | Serafim Korablev |
| Status | No release notes since February 2025 | Updated | Updated |
| Runs on | Mac | Mac, Windows, iPhone and Android | Mac |
| Phone app | None; Mac only. iOS has been on its roadmap since 2021 | iPhone, iPad and Android; on iPhone it syncs bookmarks and history with desktop Comet | Not yet |
| Price | Free; Personal Pro $20/month or Personal Max $30/month for more AI | Free; Comet Plus $5/month; Perplexity Pro $20/month or Max $200/month for more AI and agent use | Free; its AI runs on your own Claude or ChatGPT plan |
| AI | Chat about pages, on its own AI service | An agent that works in 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 | Chromium | WebKit |
| Tabs down the side | Yes | Not stated | Yes |
| Spaces | Yes | Not stated | Yes |
| Split View | Yes | Yes | Yes |
| Extensions | Chrome Web Store | Chrome Web Store | 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.
AIComet leads
Only Comet has an agent that clicks, types and finishes tasks in your pages. Airis chats about the page you are on, sums it up, looks things up and translates; no agent. Comet’s assistant answers about pages and open tabs and can click, fill forms and navigate for you, asking before it acts.
Tabs and windowsSigmaOS leads
SigmaOS has tabs down the side, spaces and Split View. Comet has Split View, folders in the sidebar and tabs that sleep.
Priceeven
SigmaOS: Free; Personal Pro $20/month or Personal Max $30/month for more AI. Comet: Free; Comet Plus $5/month; Perplexity Pro $20/month or Max $200/month for more AI and agent use.
Where it runsComet leads
SigmaOS runs on Mac. Comet runs on Mac, Windows, iPhone and Android. On a Mac, SigmaOS needs macOS 12 or later and Comet needs macOS 13 or later. SigmaOS has no phone app: Mac only. iOS has been on its roadmap since 2021. On the phone, Comet: iPhone, iPad and Android; on iPhone it syncs bookmarks and history with desktop Comet.
Engine and extensionsa matter of taste
SigmaOS is built on WebKit, the engine Safari uses; Comet on Chromium, as Chrome is. Both take extensions from the Chrome Web Store.
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. Comet keeps history, cookies and passwords on your device unless you sync; the assistant sends the page it needs to Perplexity, kept up to 30 days.
UpdatesComet leads
SigmaOS: Still downloadable, with no public release notes since version 1.19 in February 2025. Comet 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
Perplexity Comet
- Free use of the assistant is limited; more agent use is Pro at $20 or Max at $200
- No MCP server or command line from Perplexity for coding agents
- Researchers showed prompt-injection attacks on its agent in 2025 (CometJacking)
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
- August 4, 2026Comet: Ninth Circuit vacated the injunction Amazon won against Comet’s shopping agent
- March 18, 2026Comet: Comet for iPhone released
- October 2, 2025Comet: Browser made free for everyone worldwide
- 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 Perplexity Comet free?
Yes, with limits on its AI. Free; Comet Plus $5/month; Perplexity Pro $20/month or Max $200/month for more AI and agent use.
Which has an AI agent, SigmaOS or Comet?
Comet. Airis chats about the page you are on, sums it up, looks things up and translates; no agent. Comet’s assistant answers about pages and open tabs and can click, fill forms and navigate for you, asking before it acts.
Which runs on Windows, SigmaOS or Comet?
Comet does. SigmaOS runs on Mac.
Do SigmaOS and Comet have phone apps?
Comet does. SigmaOS has no phone app: Mac only. iOS has been on its roadmap since 2021. On the phone, Comet: iPhone, iPad and Android; on iPhone it syncs bookmarks and history with desktop Comet.
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 in your signed-in tabs like Comet’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
- 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
- Comet help: Operating System Requirements
- Comet help: What is Comet’s browser engine?
- Comet help: Browser features (split view, ad block, extensions, profiles)
- Comet help: Import data
- Comet help: Key settings (memory saver, tab groups)
- Comet help: Built-in password manager
- Comet help: Local data and device storage
- Comet help: Assistant privacy and data use
- Comet Quick Start Guide (Chrome import)
- Comet Assistant vs Agent
- Perplexity changelog Nov 14, 2025 (assistant asks approval before acting)
- Perplexity blog: Introducing Comet Plus ($5)
- Perplexity help: Perplexity Max
- Perplexity help: Local and remote MCPs
- App Store listing (iOS 18+, Pro $20, Max $200)
- TechCrunch: Comet now free (Oct 2, 2025)
- TechCrunch: Comet on Android (Nov 20, 2025)
- MacRumors: Comet on iPhone (Mar 18, 2026)
- Jones Day: Ninth Circuit vacates injunction (Aug 4, 2026)
- LayerX: CometJacking
- Community comet-mcp (not by Perplexity)
- Google Play: Comet: AI Browser & Assistant (updated Sep 24, 2026)
- Comet Help Center: Sync Between Devices
- Perplexity changelog: Comet iOS launch, pair mobile and desktop with device sync (Mar 27, 2026)
- Perplexity blog: Comet is now available on iOS
- Perplexity blog: Comet for Android is here
- MacStories: Comet for iOS review (sync chain, iPad version)
- 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.