Dia is an AI browser from The Browser Company of New York, the team behind Arc, built on Chromium and aimed at work. Its address bar doubles as an AI assistant that can chat with open tabs, summarize pages, draft writing and pull together briefs from connected tools such as Slack, Gmail, Notion and Atlassian's apps. Dia launched as an invite-only Mac beta on Jun 11, 2025, opened to all Mac users on Oct 9, 2025 and shipped an early Windows build on Oct 6, 2026.
Atlassian agreed on Sep 4, 2025 to buy The Browser Company for $610 million in cash and closed the deal on Oct 21, 2025. New paid AI plans for Mac users followed in Aug 2026, running up to $100 a month, and The Browser Company has said a more agentic Dia, one that carries out tasks on websites instead of only reading them, is coming in fall 2026. As of Nov 1, 2026 we haven't seen it confirmed as shipped, which is why site owners searching for Dia mostly want to know whether there is anything to detect yet.
How Dia shows up on your site
Dia runs on the user's own Mac or Windows PC and browses from their own IP, like any other browser. The Browser Company documents no Dia token in the user agent, no request signature and no IP list. When the AI reads a page, the person is the one who opened it, so the visit itself is an ordinary human page view. The AI work happens elsewhere, since Dia sends the page content and tab context to outside cloud model providers when its AI features run, including pages behind SSO, and those calls never reach your server.
| Check | What Dia does |
|---|---|
| User agent | No Dia or agent token documented |
| Web Bot Auth signature | None documented |
| IP ranges | None, traffic uses the user's own IP |
| robots.txt | Not documented |
Why Dia is hard to detect, and why it rarely matters yet
Dia is a regular Chromium browser on the person's own machine with no published marker, so there is nothing in the request to separate it from Chrome. For most of its traffic that is fine, because the AI reads along while a person browses, and that is neither automation nor a fraud concern. A rule that tried to flag Dia today would mostly flag normal customers who picked a different browser.
The open question is the agentic version. Nobody outside The Browser Company knows yet whether it will act inside the user's browser, as Comet and Claude in Chrome do, or run tasks on a cloud machine, and that choice decides which signals will matter. If it acts locally, the same behavioral traits that give away other in-browser agents, such as fields filled instantly and no mouse path between clicks, are the likely tells.
How Verisoul detects Dia
Verisoul does not name Dia, because it declares no identity and today mostly doesn't automate anything. A person browsing in Dia while the AI reads the page scores as human. If Dia, or any agent running inside it, starts clicking and typing on its own, Verisoul reads that automated input and page flow and raises the session's bot score while the agent field stays empty.
"agent": nullbot_scoreruns from 0 to 1 and rises only when the session looks automated, so 0.97 means software was driving the input and page flowagentisnullbecause Dia does not declare or sign an identity, so Verisoul does not attach a name- The device is a regular Chromium browser and the IP is the user's own, so neither raises the score on its own
If The Browser Company adds a declared identity when agentic Dia ships, Dia will get its own entry in Agent Atlas. The AI agent detection docs explain how bot score and the agent field work together.
- 01Person opens your page in Dia
- 02Dia's AI reads the page for them
- 03Your site sees a normal visit
- 04Automation, if any, raises bot score
How to detect Dia step by step
- Add the Verisoul SDK to sign-up, login, checkout and payout pages, following the AI agent detection docs
- Leave sessions with a low
bot_scorealone, since that is a person browsing with an AI reading along - Flag sessions where
bot_scoreis high andagentis null for review on risky steps - Revisit your rules when The Browser Company ships agentic Dia and documents how it runs
Should you block Dia?
No. Most Dia traffic is a person browsing with an assistant that reads along, so there is nothing to block, and blocking the browser would only turn away customers.
If an automated session does turn up in Dia, the usual rules for unnamed agents apply. Review it at sign-up, where automated account creation is the main risk, and at payouts and account changes, while browsing and checkout on a known account can stay open.