# Do AI Browsers Share Your Data? Comet vs Atlas vs Dia (2026)

> Comet's own privacy notice contradicts itself on local data. Atlas trains on your browsing only if you opt in. We quote all three policies verbatim.

- Canonical: https://www.superchargebrowser.com/library/ai-browsers-privacy-data-sharing-2026/
- Published: 2026-08-03
- Updated: 2026-08-03
- Source: SuperchargeBrowser (https://www.superchargebrowser.com)

As of August 2026, Perplexity Comet, ChatGPT Atlas, and Dia are the three AI browsers with privacy policies worth reading line by line, and the three disagree. Comet's own notice says it "does not access" locally stored browsing data, then says that same data "may be used to... recommend relevant content." Atlas keeps its browsing-training toggle off by default. Dia's AI partners are contractually barred from training on anything you send them.

> **Key takeaways**
> - **Comet's privacy notice contains its own contradiction.** It says Perplexity doesn't access locally stored browsing data, then says that data feeds recommendations. Both sentences are in the same clause.
> - **Atlas trains on your browsing only if you opt in**, though a separate diagnostic-log toggle, on by default, shares visited URLs for a different stated purpose.
> - **Atlas stops mattering in six days.** OpenAI shuts it down August 9, 2026, leaving Comet and Dia as the two AI browsers whose privacy record still needs watching.

## What "Your Data Stays Local" Actually Means, Browser by Browser

Every AI browser markets itself as respecting your privacy. The three current privacy policies say something more specific, and less uniform, than that.

Perplexity's Comet notice (last updated July 8, 2026) splits browsing data into two buckets. Saved settings and synced history are explicit: "Depending on your settings, we record your browsing history and track your use and engagement when you use Comet with your synced Perplexity account." Separately, there's data the notice calls local-only ("browsing data, permissions you have granted to websites, and records of your downloads"), which the same paragraph says Perplexity does "not access." Then the next sentence: that local data "may be used to provide and improve Comet and recommend relevant content." Not-accessing and using-to-recommend are two different claims about the same data, one paragraph apart. That's not a lie; it reads like a clause written to be defensible from two directions at once. Read it before assuming "local" means "ours to see."

OpenAI's Atlas takes the opposite approach: it names the toggle. Under Data controls, "Include web browsing" governs whether content you browse can train OpenAI's models, and per OpenAI's own help documentation, "this toggle is off by default." A second, unrelated toggle, "Help improve browsing & search," is "on by default" and shares diagnostic logs that "can include technical details and publicly known URLs." That's a different data flow, stated as reliability work rather than model training, and most users never review it separately.

Dia, from The Browser Company, publishes the shortest and plainest claim of the three: "your conversations, history, bookmarks, and files are encrypted and stored locally on your device" by default, and "Dia doesn't collect your browsing data to build ad profiles." When you do use its AI assistant, Dia's published security page names the partners handling the request (Anthropic, OpenAI, Gemini, Azure, AWS) and states they're "contractually restricted from retaining and using your data to train their own models."

## AI Training Defaults: Off, On, and Contractually Blocked

The three companies made three different defaults for the same underlying question: can a browsing session end up shaping a model?

| Browser | Trains on your browsing by default? | What you'd have to do to change it |
|---|---|---|
| Perplexity Comet | Not addressed as a distinct model-training toggle in the current notice; synced browsing history is recorded for personalization | Review Comet's browsing privacy settings (linked from the notice) |
| ChatGPT Atlas | No. "Include web browsing" training toggle is off by default | Turn it on under Data controls > Improve the model for everyone |
| Dia | No. AI partners are contractually barred from training on user data, regardless of your setting | Nothing to toggle; the restriction is contractual, not a switch |

Atlas is the only one of the three that names an explicit, user-facing on/off switch for training. Dia removes the question by contract instead of by toggle. Comet's current notice doesn't describe a distinct training toggle for browsing content the way Atlas does; it describes recording and personalization instead, which is a related but not identical claim.

## Incognito Mode Isn't What the Name Implies in Either One

Two of the three policies go out of their way to say incognito mode has limits, in nearly identical language.

Perplexity's notice: "If you use incognito mode, note that we, and third parties like the websites that you visit, may still be able to track you. Other people that use your device will not see your history from previous sessions, however."

OpenAI's help center, on Atlas: "Incognito doesn't make you invisible to ChatGPT or the rest of the internet." Signed-out chats are retained separately "for 30 days to detect and prevent abuse," and "your activity might also be seen by your employer, school, or your internet service provider."

Both companies are describing the same real limitation: incognito clears local traces on your device, not your visibility to the sites you visit, your network operator, or (in OpenAI's case) abuse-detection systems that hold your signed-out activity for a month regardless of the incognito window. Dia's public security page, as of this check, doesn't address incognito-mode limits in comparable detail. That's an absence, not a claim either way.

## Reading This Comparison With Atlas's August 9 Shutdown in Mind

OpenAI announced on July 9, 2026 that ChatGPT Atlas would stop working entirely on August 9, 2026, a 30-day wind-down, and that's six days from this comparison's access date. Every setting described above still applies to whoever is still using the browser through the shutdown, but it's a closing window, not an ongoing commitment. Atlas isn't one of the live long-term options anymore; Comet and Dia are the two whose policies are worth re-checking every few months as they get updated. (Mid-migration off Atlas yourself? The export steps are in our [Atlas shutdown guide](/library/atlas-browser-shutdown-migrate-2026/).)

## If the Real Want Is Better Tabs, Not a Cloud AI Account

None of this makes Comet, Atlas, or Dia unsafe to use. A recorded browsing history and a diagnostic log are not the same thing as the data-brokerage patterns that show up in some Chrome extensions. But all three require routing at least some of your browsing through a company's servers to get the AI features that are the whole reason to switch browsers in the first place. If what actually pulled you toward an AI browser was the workspace and tab layer, not the assistant, that part doesn't need a cloud account at all. [SuperchargeNavigation](https://chromewebstore.google.com/detail/mpkbppjbchjdohbjgeoamdehklmapgnl) adds named workspaces, an Alt+K command bar, and 5-minute session snapshots directly in Chrome, stored in `chrome.storage.local` with zero telemetry and no sign-in required; the one exception is cross-device sync, which rides your browser's own Chrome account sync rather than any server of ours, and which is on by default and can be switched off per device in settings.

If you want the AI assistant and accept a company's own read on what "improve the model" means, Comet's free, cross-platform reach beats Dia's macOS-only beta on friction alone. If you want the tab and workspace upgrade without adding a new account to the list of companies that can see what you browse, that's the extension route, and it works whichever of these browsers you end up on.

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Canonical URL: https://www.superchargebrowser.com/library/ai-browsers-privacy-data-sharing-2026/