Alternatives to SigmaOS
macOS browser that organises tabs into workspaces and treats them as tasks. The listings below can replace it for an important use case. Each note says what changes if you switch.
The original
SigmaOS
macOS browser that organises tabs into workspaces and treats them as tasks.
Replacements
Listings that take over the same core job as SigmaOS.
Arc
Chromium browser organised around spaces, a sidebar and split views.
Arc offers spaces, a sidebar and split view for free on macOS and Windows, though it requires an account and now receives limited feature work.
Zen Browser
A Firefox build with vertical tabs, workspaces and split view, aimed at people who found Arc appealing.
Zen Browser brings vertical tabs, workspaces and split view on Firefox's engine, is free and open source, and runs on Windows, macOS and Linux.
Vivaldi
A Chromium browser for people who want tab stacks, split screen and a mail client in the same window.
Vivaldi manages heavy tab loads with stacking, tiling and vertical tabs at no cost, runs on Windows, macOS and Linux, and adds built-in mail and calendar.
Floorp
A Firefox build from Japan with vertical tabs, workspaces, split view and web panels already wired in.
Floorp is a free, open-source Firefox build with vertical tabs, workspaces and split view built in, and it runs on Windows, macOS and Linux.
Safari
Apple's browser, with the deepest integration into macOS and Apple devices.
Safari trades workspaces for deep macOS integration, iCloud tab and password sync and low battery use, and is free with no paid tier.
Shift
Workspace browser for juggling several email and SaaS accounts.
Shift organises several accounts of the same services into spaces across Windows, macOS and Linux, but most spaces require a paid plan and it is memory-hungry.
Wavebox
Workspace browser for juggling many web apps and multiple accounts of the same service.
Wavebox focuses on many web apps and multiple accounts of one service across Windows, macOS and Linux, and is also closed source with a limited free tier.
Dia
AI-first browser with a chat sidebar that works across your tabs.
Dia is a macOS browser centred on an AI chat sidebar that reads your open tabs, rather than on workspaces, and it sends page content to a remote service.
Also worth comparing
These listings name SigmaOS as their own alternative, so the relationship runs both ways.
Opera Air
A browser from Opera designed to reduce distractions, with focus support and break reminders.
SigmaOS organises tabs into workspaces that can be marked done or locked like tasks, but is macOS only and pushes regular users to a paid plan.
Similar software
Related functionality, not a direct replacement.
Perplexity Comet
Agentic browser with a built-in research assistant and task automation.
Opera
Chromium browser with an ad blocker, a free proxy VPN and a messenger sidebar.
Microsoft Edge
Microsoft's Chromium-based browser, bundled with Windows.
Naver Whale
Korean Chromium browser with a sidebar, split tabs and built-in capture tools.
