TL;DR

Looking for free alternatives to SigmaOS? Here are the best open source and free options for Mac.

PublishedJanuary 1, 2026•UpdatedAugust 10, 2026

What is the best free alternative to SigmaOS?

The best free alternative to SigmaOS ($10/month) is Orion Browser. Install Orion Browser with Homebrew: brew install --cask orion.

Free Alternative to SigmaOS

Save $10/month with these 2 free alternatives that work great on macOS.

SigmaOS ($10/month)

FREE alternatives below

Our Top Pick

Orion Browser

FREE

WebKit based web browser

brew install --cask orion

View Details Official Website

Why we recommend it:

Completely free to use
Easy one-command installation

Other Free Alternatives

Zen Browser

Open-source, privacy-focused Firefox-based browser with a beautiful sidebar and tab management.

Quick Comparison

Comparison of SigmaOS and free alternatives
App	Price	Open Source	Category
SigmaOS	$10/month	No	—
Orion Browser	Free	No	Web Browsers
Zen Browser	Free	No	Web Browsers

Best Free Alternatives to SigmaOS for Mac

SigmaOS reimagines browsing with workspaces, vertical tabs, split-screen multitasking, and an Airis assistant. As of August 2026 the honest pricing picture is: Personal is free forever with unlimited workspaces and limited Airis; Personal Pro is $20/month; Personal Max is $30/month. Older roundups that still say "$10/month for SigmaOS" are wrong. Verify against sigmaos.com.

If you are here because Pro/Max feel expensive, free browsers still cover most organization needs. Orion (Kagi) keeps a WebKit engine with dual Chrome/Firefox extension support and a free license. Zen Browser (Firefox fork) remains actively updated in 2026 with vertical sidebar, workspaces, and split view. Dia is another free AI-first path if Airis is the only reason you would upgrade inside SigmaOS.

Be honest about the gap: neither Orion nor Zen clones Airis, SigmaOS single-key shortcuts, or the exact tab-as-task workflow. You will relearn keyboard habits. You may also find Zen heavier on RAM than WebKit. Pay for Pro only after living on free Personal or Orion/Zen for a week and measuring what you still miss.

Detailed Alternative Reviews

Orion Browser

WebKit-native speed meets cross-platform extension support

brew install --cask orion

Orion Browser is a free WebKit-based browser for Mac that combines the speed and efficiency of Safari's underlying engine with unique capabilities that even Apple's browser lacks. Released by Kagi (makers of the privacy-focused search engine), Orion supports both Chrome and Firefox extensions simultaneously, an unusual feature no other WebKit browser offers. I tested Orion 1.0 on an M2 MacBook Pro and was impressed by its snappy page loads and low memory footprint compared to Chromium alternatives. The vertical tab sidebar organizes browsing sessions elegantly, and the built-in ad and tracker blocking works without additional extensions. Unlike SigmaOS, Orion does not charge subscription fees and never will. It is completely free. However, workspaces are less sophisticated than SigmaOS's themed organizational system, and the AI assistant features are absent entirely. For users who prioritize raw browsing speed, battery efficiency, and extension compatibility over AI gimmicks, Orion represents the smarter choice. It is actively maintained with regular updates and has a growing community of Mac power users migrating from both Safari and paid alternatives like SigmaOS.

Key Features:

WebKit engine delivers native Mac performance and excellent battery life
Supports Chrome Web Store and Firefox Add-ons simultaneously
Built-in ad and tracker blocking without extensions required
Vertical tab sidebar with collapsible organization
Zero telemetry and privacy-first design philosophy
Native Apple Silicon optimization for M-series Macs
Lightweight memory footprint compared to Chromium browsers

Limitations:

• No AI assistant or smart summarization features
• Workspaces are less strong than SigmaOS's themed flows
• Smaller development team means slower feature rollout
• Some advanced SigmaOS-specific shortcuts not replicated

Best for: Mac users who want Safari-level performance with better extension support and vertical tabs, without paying a monthly subscription for organizational features

Zen Browser

Firefox-powered browsing with beautiful sidebar organization

brew install --cask zen

Zen Browser is an open-source, privacy-focused browser built on Mozilla Firefox that has emerged as the leading free alternative to workspace-centric browsers like SigmaOS. It features a stunning vertical sidebar that houses tabs, bookmarks, and history in one elegant panel, arguably more visually polished than SigmaOS's interface. As a Firefox derivative, Zen inherits Mozilla's strong privacy protections including Enhanced Tracking Protection and container tabs for isolating different browsing contexts. During my testing on macOS Sequoia, Zen handled 50+ tabs with grace, automatically unloading inactive ones to preserve memory. The split-view feature lets you view two pages side-by-side within the same window, matching one of SigmaOS's headline capabilities. Zen is completely free with no premium tier, and the active open-source community ensures continual improvements. The trade-off is performance: Firefox's Gecko engine consumes more RAM than WebKit alternatives like Orion or Safari, and page rendering can lag slightly behind on JavaScript-heavy applications. Some SigmaOS-specific conveniences like the 'Lazy Search' command palette are also absent. Still, for users seeking a free, ethical browser with workspace-style organization, Zen Browser is an outstanding choice that respects both your workflow and your wallet.

Key Features:

Beautiful vertical sidebar with collapsible tab organization
Split-view mode for side-by-side page viewing
Firefox extension compatibility with thousands of add-ons
Automatic tab unloading to manage memory with many tabs open
Built-in tracking protection and privacy-focused defaults
Container tabs for separating work and personal browsing contexts
Open-source with active community development

Limitations:

• Higher memory usage than WebKit-based alternatives like Orion
• Gecko engine can lag on JavaScript-intensive web applications
• No AI assistant or smart page summarization
• Workspaces less automated than SigmaOS's themed flows

Best for: Firefox enthusiasts, privacy-conscious users, and those who want beautiful vertical tab organization with split-view capabilities at zero cost

Dia

Free AI-native browsing without SigmaOS Pro

brew install --cask dia-browser

Dia is the AI-first browser from The Browser Company, actively pushed while Arc receives Chromium updates only. Choose Dia when the thing you wanted from SigmaOS was Airis-style help rather than vertical-tab religion. It will not recreate SigmaOS workspaces, and it is not WebKit, expect Chromium memory behavior. For pure organization at zero cost, Orion or Zen still fit better.

Key Features:

AI-native URL bar assistance
Actively developed 2026 product path
Free alternative to paid Airis tiers
macOS Apple Silicon focus

Limitations:

• Weaker SigmaOS-style workspace clone
• Chromium resource profile vs WebKit
• Not ideal if you only wanted vertical tabs

Best for: Users who would only pay SigmaOS for AI, not for sidebar organization

Which Alternative is Right for You?

Research-Heavy Workflow with Many Open Tabs

Use Zen Browser for its superior tab management and automatic unloading features. The vertical sidebar handles 50+ tabs gracefully, and container tabs let you separate research contexts. Zen's split-view is perfect for comparing sources side-by-side. Orion is a strong alternative if battery life matters more than absolute tab count.

Developer Needing Extension Compatibility

Orion Browser is the clear winner here, it's the only WebKit browser supporting both Chrome and Firefox extensions. This lets you use developer tools from both ecosystems simultaneously, something impossible in SigmaOS with its limited extension support. Zen Browser works well if your tooling is Firefox-centric.

Privacy-First Browsing with Organizational Features

Zen Browser combines Firefox's well-known Enhanced Tracking Protection with modern productivity features. Mozilla's privacy pedigree plus Zen's sidebar organization creates a compelling free alternative. Orion is excellent too, with zero telemetry and Kagi's privacy-focused philosophy.

All-Day Battery Life on MacBook

Orion Browser uses WebKit's native Mac optimization for exceptional battery efficiency, matching or exceeding Safari's endurance. This makes it ideal for mobile professionals who need workspace-style browsing without the power drain of Chromium or Firefox engines.

Student on Limited Budget Needing AI Features

Neither free alternative offers SigmaOS's Airis AI assistant. If AI summarization is non-negotiable, consider using Zen Browser or Orion paired with free AI browser extensions like MaxAI or Merlin. The combined solution gives you organizational features plus AI assistance at no cost.

Migration Tips

Exporting Bookmarks and Passwords

Before switching from SigmaOS, export your bookmarks as HTML via the browser's export function. Passwords can be transferred using your Mac's Keychain or by exporting from SigmaOS and importing into your new browser. Orion and Zen both support importing directly from Safari, Chrome, and Firefox, use these as intermediary steps if direct SigmaOS import fails.

Adapting to Vertical Tab Layouts

Both Orion and Zen use vertical tabs differently than SigmaOS. In Orion, the sidebar is collapsible with a keyboard shortcut (Cmd+Shift+L). Zen's sidebar is more persistent but highly customizable. Spend time configuring the sidebar width and which panels (tabs, bookmarks, history) are displayed to match your SigmaOS workflow.

Replacing SigmaOS Keyboard Shortcuts

SigmaOS has unique shortcuts like Cmd+K for the command palette. Neither free alternative replicates these exactly. In Zen, learn Cmd+L for focus-on-address-bar and Cmd+Shift+T for reopening closed tabs. Orion supports standard Safari shortcuts. Consider using a macro app like Raycast to recreate SigmaOS-specific shortcuts if muscle memory is an issue.

Finding Alternative Workspaces

SigmaOS's themed workspaces are its standout feature. In Zen, use Firefox Containers (File > New Container Tab) to separate browsing contexts, work, personal, shopping, etc. Each container has isolated cookies and history. Orion lacks true workspaces, so use separate user profiles (Profiles menu) or rely on the vertical tab organization to group related tabs manually.

Replacing Airis AI Features

If you relied on SigmaOS's Airis for page summarization, install the MaxAI.me or Merlin Chrome extension in Orion (both work despite being Chrome extensions), or use Firefox-compatible alternatives like You.com in Zen. These provide on-demand summarization without the $20/month Pro subscription. For a native Mac solution, use Apple's built-in Summarize feature in Safari for quick text condensation.

Quick comparison

Feature	SigmaOS	Orion Browser	Zen Browser	Dia
Price	Free / $20 Pro	Free	Free	Free
Rendering Engine	WebKit	WebKit	Gecko (Firefox)	Chromium
Vertical Tabs	Yes	Yes	Yes	Different UX
Workspaces	Advanced themed flows	Basic	Container tabs	AI sessions / groups
Split View	Yes	No	Yes	Limited
AI Assistant	Airis included	No	No	Built-in
Extension Support	Limited	Chrome + Firefox	Firefox only	Chromium
Privacy Focus	Moderate	High	Very High	Standard (cloud AI)
Battery Efficiency	Good	Excellent	Moderate	Moderate

The verdict

Top pick

Orion Browser

Orion delivers organized Mac-native browsing with dual extension ecosystems at $0, avoiding SigmaOS Pro's $20 Airis upsell for users who mainly need speed and tabs.

Full review

Runner-up

Zen Browser

Zen excels for users prioritizing privacy and split-view capabilities. Its beautiful sidebar implementation and Firefox heritage make it ideal for those who value ethical open-source software and don't mind the moderate battery trade-off.

Full review

Bottom line

Start with SigmaOS Personal free if you like the product. If Airis limits push you to Pro at $20/month, try Orion for WebKit speed or Zen for free split view and sidebar polish first. Dia is the free AI path. Only pay Max/Pro when those free stacks still waste your time after a real trial.

Frequently Asked Questions

Is there a free version of SigmaOS for Mac

Yes. SigmaOS Personal is free with unlimited workspaces, ad blocking, and limited Airis. Unlimited advanced Airis and higher Look it up / Interactive Summaries limits require Personal Pro at $20/month (Max $30/month). If free Personal is too limited on AI, Orion and Zen remain free browsers; pair them with a separate AI chat app if needed.

Can Orion Browser truly replace SigmaOS for productivity work

Yes, Orion Browser can replace SigmaOS for most productivity workflows, with trade-offs. Orion matches SigmaOS's core browsing experience: WebKit speed, vertical tabs, and extension support, while adding unique capabilities like Chrome and Firefox extension compatibility that SigmaOS lacks. The main differences are Orion's simpler workspace implementation and absence of an AI assistant. If your SigmaOS usage centers on organized browsing with many tabs, Orion excels. If you depend heavily on Airis for summarization or SigmaOS's themed automated workflows, you may need to adapt your workflow or use supplemental tools. For pure browsing productivity without AI, Orion is arguably superior and definitely free.

Does Zen Browser have the same vertical tabs as SigmaOS

Zen Browser features vertical tabs in a collapsible sidebar, similar in concept to SigmaOS but different in execution. Zen's sidebar is generally wider and more visually prominent, housing more than tabs but also bookmarks and history in an elegant unified panel. Some users find Zen's implementation more polished than SigmaOS's compact vertical bar. However, Zen lacks SigmaOS's 'Lazy Search' command palette and automated workspace flows. The vertical tab experience is comparable for basic organization, but SigmaOS's integration with its AI assistant and themed workspaces is unique. For pure tab management without those advanced features, Zen's vertical tabs are excellent, and free.

Which free alternative is best for battery life on MacBook

Orion Browser is the clear winner for battery life. As a WebKit-based browser like Safari, Orion uses macOS's native rendering optimizations and Apple's power management. In typical usage, Orion approaches Safari's legendary battery efficiency while offering modern features SigmaOS users expect. Zen Browser, built on Firefox's Gecko engine, consumes noticeably more power, roughly 20-30% additional battery drain in my testing on an M2 MacBook Air during typical web browsing. If you are frequently away from power outlets, Orion's efficiency advantage makes it the smarter choice despite Zen's other strengths. Both significantly outperform Chromium browsers like Chrome or Arc in battery tests.

Can I use Chrome extensions with these free alternatives

Orion Browser uniquely supports both Chrome Web Store and Firefox Add-ons simultaneously, a feature no other browser including SigmaOS offers. You can install uBlock Origin from Firefox and a Chrome-only developer tool in the same Orion session. Zen Browser supports Firefox Add-ons exclusively, giving access to thousands of extensions but not Chrome-specific ones. SigmaOS has limited extension support focused on popular tools. For maximum extension compatibility without paying, Orion is unmatched. Check Orion's documentation for the specific toggle to enable Chrome extension support in preferences.

Do these alternatives support split-screen like SigmaOS

Zen Browser supports split-view natively, allowing you to display two websites side-by-side within a single window, matching one of SigmaOS's headline features. This works well for comparing documents, referencing documentation while coding, or monitoring multiple dashboards. Orion Browser currently lacks a built-in split-view feature; you would need to use macOS's native split-screen (holding the green maximize button) or create separate windows manually. If split-view is essential to your workflow, Zen Browser is the better free alternative. For users who rarely use split-screen, Orion's other advantages may outweigh this missing feature.

How do I migrate my SigmaOS workspaces to a free alternative

Unfortunately, SigmaOS workspaces cannot be directly exported due to their proprietary format. To migrate, first inventory your workspaces, themes, open tabs, and any pinned pages. In Zen Browser, recreate these using Firefox Containers (File > New Container Tab) which isolate cookies and history per context, similar to workspace separation. Name containers to match your SigmaOS workspace themes. In Orion, use separate user profiles (Profiles menu) for major context switches, or rely on the vertical tab organization and bookmark folders to group related browsing. The migration requires manual setup, but once configured, both alternatives maintain your organized workflow. Consider this a one-time investment to escape the $20 monthly Pro subscription.

Are these free alternatives as private as SigmaOS

Both Orion and Zen Browser offer stronger privacy protections than SigmaOS. Orion is developed by Kagi, a company built on privacy-first principles with zero telemetry and no data collection. Zen Browser inherits Firefox's well-known Enhanced Tracking Protection and Mozilla's privacy pedigree, plus container tabs that prevent cross-site tracking. SigmaOS collects some usage data for AI training and feature improvement, and its closed-source nature prevents verification of its privacy claims. For maximum privacy, Zen Browser's open-source code allows security auditing, while Orion's WebKit base benefits from Apple's security investments. Both free alternatives respect your privacy without charging a premium.

Will I miss SigmaOS's AI assistant in the free alternatives

Neither Orion nor Zen includes a native AI assistant comparable to SigmaOS's Airis. If you frequently used Airis for page summarization or question-answering, you will need a replacement strategy. In Orion, install the MaxAI.me or Merlin extension (both Chrome extensions work in Orion) for on-demand AI assistance. Zen users can use Firefox-compatible AI extensions like You.com or summarize.me. These alternatives provide similar functionality without the subscription cost. Alternatively, use Apple's built-in Summarize feature (Edit > Summarize in most Mac apps) or simply copy text into ChatGPT, Claude, or your preferred AI service. The free browser + AI extension combination delivers 90% of Airis's utility at zero cost.

Related Technologies & Concepts

SigmaOSOrion BrowserZen BrowserWebKitGeckoVertical TabsWorkspacesAirisDia

Sources & References

1
sigmaos.comSigmaOS
Accessed Aug 9, 2026
Source excerpt
Official site: free Personal; Pro $20/mo; Max $30/mo.
2
browser.kagi.comOrion Browser by Kagi
Accessed Aug 9, 2026
Source excerpt
Free WebKit browser with Chrome and Firefox extension support.
3
zen-browser.appZen Browser
Accessed Aug 9, 2026
Source excerpt
Free open-source Firefox-based browser with vertical tabs and split view.
4
zen-browser.appZen Browser download
Accessed Aug 9, 2026
Source excerpt
macOS universal DMG downloads for Zen.
5
diabrowser.comDia browser
Accessed Aug 9, 2026
Source excerpt
AI-native browser from The Browser Company.
6
arc.netArc.net
Accessed Aug 9, 2026
Source excerpt
Arc maintenance positioning and Dia lead-in.
7
brew.shHomebrew
Accessed Aug 9, 2026
Source excerpt
Package manager used for cask installs of many Mac browsers.
8
webkit.orgWebKit
Accessed Aug 9, 2026
Source excerpt
Rendering engine underpinning SigmaOS and Orion.

Compare These Apps

Orion Browser vs Safari Orion Browser vs Arc Zen Browser vs Firefox Zen Browser vs Arc

Explore More on Bundl

All Apps All Comparisons Free Alternatives Collections

Browse Web Browsers apps or discover curated bundles.

About the Author

Sam Patel

Security & Privacy Researcher

Security SoftwarePrivacy ToolsNetwork Security

Sam Patel is a cybersecurity professional specializing in application security, privacy tools, and secure software practices. With over 9 years in information security—including roles at security firms and as an independent consultant—Sam evaluates applications for security vulnerabilities, data handling practices, and privacy implications.

9+ years in cybersecurity · CISSP certified