YabZen is a free, open-source browser built on Firefox that brings Arc’s layout, tabs down the side with spaces, folders and Split View, to Mac, Windows and Linux.
Dia is the AI browser The Browser Company builds now instead of Arc. It is Chromium-based, for Macs with Apple silicon and, since October 2026, Windows, and its AI chats with your tabs and the tools you connect.
The short answer
- if you want Arc’s layout, free and open source
- if you prefer Firefox’s engine and its add-ons
- if you want no AI in your browser at all
- if you want the current browser from Arc’s makers, with Arc import and tabs down the side as a setting
- if you want AI that chats across your tabs, Gmail, Slack and Notion, and will pay for it
- if you want a free browser with an ad blocker and no AI
- 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
Zen and Dia, with Yab beside them for a Mac.
| What | Zen Browser | Dia | Yab |
|---|---|---|---|
| Made by | Zen Browser team (open-source community project) | The Browser Company (Atlassian) | Serafim Korablev |
| Status | Updated | Updated | Updated |
| Runs on | Mac, Windows and Linux | Mac and Windows | Mac |
| Phone app | None; Zen says it has no plans for a mobile version | None | Not yet |
| Price | Free and open source | Browser free; AI on Better Answers $20/month or Better Days $100/month | Free; its AI runs on your own Claude or ChatGPT plan |
| AI | No AI | 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 | Gecko | Chromium | WebKit |
| Tabs down the side | Yes | A setting | Yes |
| Spaces | Yes | Yes | Yes |
| Split View | Yes | Yes | Yes |
| Extensions | Firefox add-ons | Chrome Web Store | Chrome Web Store |
| Ad blocker | No | Built in | Built in |
| Open source | Yes | 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.
AIDia leads
Dia has AI built in; Zen has less of it. Zen has no AI: Firefox’s AI features are switched off by default. Dia chats with your tabs and the tools you connect, like Gmail, Slack and Notion, and drafts mail and invites; there is no documented agent that works through sites.
Tabs and windowsZen leads
Zen has tabs down the side, spaces, Split View, folders in the sidebar and tabs that sleep. Dia has tabs down the side as a setting, spaces, Split View, folders in the sidebar and tabs that sleep.
Priceeven
Zen: Free and open source. Dia: Browser free; AI on Better Answers $20/month or Better Days $100/month.
Where it runsZen leads
Zen runs on Mac, Windows and Linux. Dia runs on Mac and Windows. On a Mac, Zen needs macOS 10.15 or later and Dia needs macOS 14 or later. Zen has no phone app: Zen says it has no plans for a mobile version. Dia has no phone app.
Engine and extensionsa matter of taste
Zen is built on Gecko, Firefox’s engine; Dia on Chromium, as Chrome is. Zen takes extensions from Firefox’s add-ons, Dia from the Chrome Web Store.
Privacyeven
Zen has open code. Zen sends no telemetry or crash reports, by its privacy policy; optional sync keeps encrypted data on Mozilla’s servers. Dia has an ad blocker built in. Dia’s chat goes through its servers to Anthropic, OpenAI and Google; chats and history stay on your Mac, and content sharing is on by default, kept 30 days.
What their pages don’t lead with
Real limits, from the makers’ own words and our own use.
Zen Browser
- Releases are still labeled beta
- No phone app, and none planned
- Firefox add-ons only, not the Chrome Web Store
- No ad blocker of its own beyond Firefox’s tracking protection
Dia
- AI costs $20 or $100 a month for new users; the free plan has none after a 14-day trial
- On a Mac it needs Apple silicon and macOS 14 or later
- Its AI chats and drafts, but there is no documented agent that works through sites
- No MCP server or command line for outside agents
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 6, 2026Dia: Dia 1.0 for Windows released
- September 5, 2026Zen: Spaces, folders and tabs sync between devices with a Mozilla account (1.22b)
- August 17, 2026Dia: Paid AI plans started rolling out to new Mac users
- February 28, 2026Zen: Live folders for GitHub issues, pull requests and RSS (1.19b)
- October 21, 2025Dia: Atlassian completed its acquisition of The Browser Company
- August 27, 2025Zen: Tab folders added (1.15b)
Questions
Is Zen Browser free?
Yes. Free and open source.
Is Dia free?
The browser is; its AI isn’t. Browser free; AI on Better Answers $20/month or Better Days $100/month.
Which has an AI agent, Zen or Dia?
Neither has an agent that does tasks in your pages. Zen has no AI: Firefox’s AI features are switched off by default. Dia chats with your tabs and the tools you connect, like Gmail, Slack and Notion, and drafts mail and invites; there is no documented agent that works through sites.
Do Zen and Dia run on Windows?
Yes, both. Zen runs on Mac, Windows and Linux; Dia on Mac and Windows.
Do Zen and Dia have phone apps?
Zen has no phone app: Zen says it has no plans for a mobile version. Dia has no phone app.
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 Zen; 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
- Zen home page
- Zen download page (macOS universal, Windows, Linux; beta)
- Zen 1.23.2b release (macOS universal dmg; Info.plist minimum 10.15)
- Zen 1.23.1b release (Firefox 157.0.1)
- Zen license (MPL-2.0)
- Zen AI preferences (all off)
- Zen welcome flow (Firefox import wizard)
- Firefox import from another browser
- Zen 1.15b release (folders)
- Zen 1.19b release (live folders)
- Zen 1.22b release (sync)
- Zen 1.12.9b release (tab unloader uses Firefox tab discarding)
- Zen FAQ (no mobile plans, donations)
- Zen Workspaces
- Zen Split View
- Zen Extensions (addons.mozilla.org)
- Zen Privacy and Security (Firefox password manager, tracking protection)
- Zen privacy policy
- Firefox 157 system requirements
- Dia plans and pricing FAQ
- Dia home page (macOS and Windows, ad and tracker blocking)
- Dia changelog (Chromium M155, Windows 1.0, tab sleep, sidebar or top tabs, AppleScript, memory retired)
- Dia release notes 1.52.0 (Oct 8, 2026)
- Dia download FAQ (import from Chrome, Safari, Edge, Arc)
- Dia security (AI providers, retention, local storage)
- MacRumors: Dia generally available, macOS 14 and Apple silicon
- PiunikaWeb: Dia $20 and $100 plans (Aug 18, 2026)
- Atlassian completes acquisition (Oct 21, 2025)
- Dia home page: ’Available for macOS and Windows’
- PiunikaWeb: Dia ’iPhone Tabs’ menu spotted, no public app (2026-08-25)
- 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.