SigmaOS vs Aside

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.

Aside is an AI agent browser from a Y Combinator startup, on Chromium, for Mac and Windows. Its agent does multi-step work in the sites you are signed in to, on Aside’s own models or your ChatGPT or Claude plan.

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 Aside

if you want an agent for multi-step work across your signed-in sites, on Mac or Windows
if you want a free plan with AI credits, or to bring your ChatGPT or Claude plan
if you want Claude Code or Codex to drive it over MCP or its command line

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 Aside, with Yab beside them for a Mac.

SigmaOS vs Aside
What	SigmaOS	Aside	Yab
Made by	SigmaOS Inc. (London)	Aside Computer Inc. (YC Fall 2025)	Serafim Korablev
Status	No release notes since February 2025	Updated	Updated
Runs on	Mac	Mac and Windows	Mac
Phone app	None; Mac only. iOS has been on its roadmap since 2021	None yet; an iPhone app is in the works. Pro runs its agent from Slack or Telegram	Not yet
Price	Free; Personal Pro $20/month or Personal Max $30/month for more AI	Free with 500 AI credits a month; Pro $20/month; Max $200/month; or your own ChatGPT or Claude plan	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 or yours	An agent that works in pages, on your Claude or ChatGPT plan
Driven by outside agents	No	MCP and a command line	MCP and a command line
Engine	WebKit	Chromium	WebKit
Tabs down the side	Yes	Yes	Yes
Spaces	Yes	Yes	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.

AIAside leads

Only Aside 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. Aside’s agent runs multi-step tasks in your signed-in sites, signs in from its own password vault without seeing the passwords, and asks before payments, posts and messages.

Agents like Claude Code and CodexAside leads

SigmaOS has no MCP server or command line for outside agents. Aside can be driven over MCP and a command line, through the aside command line, with aside mcp as its MCP server.

Tabs and windowsAside leads

SigmaOS has tabs down the side, spaces and Split View. Aside has tabs down the side, spaces, 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. Aside: Free with 500 AI credits a month; Pro $20/month; Max $200/month; or your own ChatGPT or Claude plan.

Where it runsAside leads

SigmaOS runs on Mac. Aside runs on Mac and Windows. On a Mac, SigmaOS needs macOS 12 or later and Aside needs macOS 15 or later. SigmaOS has no phone app: Mac only. iOS has been on its roadmap since 2021. Aside has no phone app yet: an iPhone app is in the works. Pro runs its agent from Slack or Telegram.

Engine and extensionsa matter of taste

SigmaOS is built on WebKit, the engine Safari uses; Aside 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. Aside keeps task transcripts and files on your Mac; model providers get the prompts, page snapshots and screenshots a task needs, and analytics sharing is on by default.

UpdatesAside leads

SigmaOS: Still downloadable, with no public release notes since version 1.19 in February 2025. Aside 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

Aside

The free plan has 500 AI credits a month; more is Pro at $20 or Max at $200
Mac (macOS 15 or later) and Windows only, no phone apps
Young: first released in February 2026, on Windows since September 2026
Agents may use your saved passwords unless you change the default

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

September 21, 2026Aside: Ad blocking with default filter lists turned on during setup
September 14, 2026Aside: Windows version officially available (release 1.0.914.1)
February 25, 2026Aside: First Aside Browser release for macOS
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 Aside free?

Yes, with limits on its AI. Free with 500 AI credits a month; Pro $20/month; Max $200/month; or your own ChatGPT or Claude plan.

Which has an AI agent, SigmaOS or Aside?

Aside. Airis chats about the page you are on, sums it up, looks things up and translates; no agent. Aside’s agent runs multi-step tasks in your signed-in sites, signs in from its own password vault without seeing the passwords, and asks before payments, posts and messages.

Which runs on Windows, SigmaOS or Aside?

Aside does. SigmaOS runs on Mac.

Do SigmaOS and Aside have phone apps?

SigmaOS has no phone app: Mac only. iOS has been on its roadmap since 2021. Aside has no phone app yet: an iPhone app is in the works. Pro runs its agent from Slack or Telegram.

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 Aside’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 vs Arc SigmaOS vs Vivaldi SigmaOS vs Zen SigmaOS vs Orion SigmaOS vs Chrome SigmaOS vs Safari SigmaOS vs Edge SigmaOS alternatives Yab vs SigmaOS Aside vs Dia Aside vs Comet Aside vs Atlas Aside vs Opera Neon Aside vs Chrome Aside vs Safari Aside vs Edge Aside alternatives Yab vs Aside

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.

it’s freeMove from Aside Download