YabChatGPT Atlas was OpenAI’s Chromium browser for the Mac, with ChatGPT beside every page and an agent mode. OpenAI shut it down on August 9, 2026, and points people to the ChatGPT desktop app and its Chrome extension.
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.
Atlas shut down on August 9, 2026; Dia is still made, by The Browser Company. Dia’s AI chats with your tabs but doesn’t act for you the way Atlas’s agent mode did.
The short answer
- OpenAI shut Atlas down on August 9, 2026: it may not open, runs no agent tasks and gets no security updates
- 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
Atlas and Dia, with Yab beside them for a Mac.
| What | ChatGPT Atlas | Dia | Yab |
|---|---|---|---|
| Made by | OpenAI | The Browser Company (Atlassian) | Serafim Korablev |
| Status | Shut down August 9, 2026 | Updated | Updated |
| Runs on | Mac | Mac and Windows | Mac |
| Phone app | None; Atlas was Mac only and shut down on Aug 9, 2026 | None | Not yet |
| Price | Shut down; it was free, with agent mode on paid ChatGPT plans | 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 | An agent that works in pages, on its own AI service | 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 | Chromium | Chromium | WebKit |
| Tabs down the side | A setting | A setting | Yes |
| Spaces | Not stated | Yes | Yes |
| Split View | Not stated | Yes | Yes |
| Extensions | Chrome Web Store | Chrome Web Store | Chrome Web Store |
| Ad blocker | Not stated | 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.
AIAtlas leads
Only Atlas has an agent that clicks, types and finishes tasks in your pages. Atlas put ChatGPT beside every page, with optional browser memories and, on paid plans, an agent mode; it no longer works. 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 windowsDia leads
Atlas has tabs down the side as a setting and folders in the sidebar. Dia has tabs down the side as a setting, spaces, Split View, folders in the sidebar and tabs that sleep.
PriceDia leads
Atlas: Shut down; it was free, with agent mode on paid ChatGPT plans. Dia: Browser free; AI on Better Answers $20/month or Better Days $100/month.
Where it runsDia leads
Atlas runs on Mac. Dia runs on Mac and Windows. On a Mac, Atlas needs macOS 14.2 or later and Dia needs macOS 14 or later. Atlas has no phone app: Atlas was Mac only and shut down on Aug 9, 2026. Dia has no phone app.
Engine and extensionsa matter of taste
Both are built on Chromium, as Chrome is, so sites work as they do in Chrome. Both take extensions from the Chrome Web Store.
PrivacyDia leads
Atlas has no ad blocker of its own. Atlas summed up pages for browser memories and deleted the originals; training on browsing was off by default. 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.
UpdatesDia leads
Atlas: OpenAI shut Atlas down on August 9, 2026: it may not open, runs no agent tasks and gets no security updates. Dia is updated as usual.
What their pages don’t lead with
Real limits, from the makers’ own words and our own use.
ChatGPT Atlas
- Shut down on August 9, 2026, with no more security updates
- Was Mac only, on Apple silicon
- Bookmarks, tabs and history had to be exported by hand
- Agent mode needed a paid ChatGPT plan
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
- August 17, 2026Dia: Paid AI plans started rolling out to new Mac users
- August 9, 2026Atlas: Atlas shut down
- July 9, 2026Atlas: OpenAI said it will sunset Atlas for the new ChatGPT desktop app
- October 21, 2025Atlas: Launched for macOS
- October 21, 2025Dia: Atlassian completed its acquisition of The Browser Company
Questions
Is ChatGPT Atlas free?
It no longer works. Shut down; it was free, with agent mode on paid ChatGPT plans.
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, Atlas or Dia?
Atlas. Atlas put ChatGPT beside every page, with optional browser memories and, on paid plans, an agent mode; it no longer works. 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.
Which runs on Windows, Atlas or Dia?
Dia does. Atlas runs on Mac.
Do Atlas and Dia have phone apps?
Atlas has no phone app: Atlas was Mac only and shut down on Aug 9, 2026. Dia has no phone app.
Is ChatGPT Atlas shut down?
OpenAI shut Atlas down on August 9, 2026: it may not open, runs no agent tasks and gets no security updates.
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 Dia; an agent in your signed-in tabs like Atlas’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
- OpenAI help: Evolving Atlas into ChatGPT (retirement notice)
- OpenAI help: Atlas release notes (vertical tabs, tab groups, imports, profiles)
- OpenAI help: Getting started with Atlas (macOS 14.2, Apple silicon)
- OpenAI help: Setting up Atlas (imports, password manager)
- OpenAI help: Atlas data controls and privacy
- 9to5Mac: OpenAI is discontinuing Atlas (Jul 9, 2026, James Sun quote)
- 9to5Mac: what happens when Atlas shuts down (Aug 4, 2026)
- TechRepublic: Atlas shuts down Aug 9
- TechCrunch: Atlas launch (Oct 21, 2025)
- Wikipedia: ChatGPT Atlas (Chromium, timeline)
- OpenAI Help: ChatGPT Atlas retirement
- OpenAI Help: ChatGPT release notes (Jul 9, 2026 deprecation entry)
- TechRadar: Atlas for macOS, Windows, iOS and Android ’coming soon’ (Oct 2025)
- 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.