The browser wars are back, and this time the weapon is agency: browsers that don't just show you the web but act on it — researching across tabs, filling forms, comparing products, booking the thing. Three contenders matter in 2026: Perplexity Comet (free everywhere), ChatGPT Atlas (deepest agent, Mac-only) and Dia (now Atlassian's, built for SaaS workflows).
We may earn a commission if you subscribe through our links; verdicts come from daily driving all three. See our affiliate disclosure.
The 30-second verdict
| Comet | ChatGPT Atlas | Dia | |
|---|---|---|---|
| Agent mode | Free | Paid plan ($20+/mo) | Pro $20/mo |
| Platforms | Mac · Win · iOS · Android | macOS (Apple Silicon) only | macOS only |
| Built around | Cited research | Your ChatGPT memory | Repeatable workflows |
| Best for | Most people | ChatGPT power users | SaaS-heavy knowledge work |
Comet: the one that made agentic browsing free
Since March 2026, the full Comet browser — agent mode included — is free on every major platform. That single decision ended the debate for most people. You get Perplexity's citation-backed answers native to every tab, context that spans everything you have open, and an agent that handles "compare these three, summarize the differences, draft the email." Paid tiers exist (Comet Plus at $5/mo for publisher content, Perplexity Pro at $20/mo for stronger models and the Background Assistant), but the core experience costs nothing.
Atlas: the deepest agent, behind two gates
ChatGPT Atlas does the most impressive agentic work of the three — multi-step tasks that chain across sites, powered by browser memories tied to your ChatGPT history. The catch is two gates: it's macOS-only (Apple Silicon), and Agent Mode needs a paid ChatGPT plan. If you're already a ChatGPT Plus subscriber on a Mac, it's a genuine upgrade to how you work. If you're not, it's not worth switching ecosystems for.
Dia: the dark horse Atlassian bought
Dia (from the Arc team, now an Atlassian product) bet on skills — repeatable workflows you teach once and reuse: "summarize this ticket and draft a standup note," "turn this thread into a Jira issue." For knowledge workers living in SaaS tools it's quietly excellent, but Mac-only plus $20/mo for Pro keeps it a niche pick until the Atlassian integration story matures.
The security caveat nobody puts in the headline
An agentic browser is an AI with your logged-in sessions. Prompt-injection — malicious instructions hidden in webpages that hijack the agent — is a real, unsolved problem across all three. The sane rules: keep agent mode away from banking and health portals, use a separate browser profile for sensitive accounts, and review what an agent did before trusting what it says it did. Our guide to using AI safely covers the wider hygiene.
Which one should you pick?
- Most people: Comet — free, everywhere, and the research experience alone justifies the switch. (Perplexity vs ChatGPT as assistants is a different question — we compared them here.)
- ChatGPT-centric Mac users: Atlas — your memory and custom instructions follow you across the web.
- Jira/Confluence teams on Macs: watch Dia closely; the Atlassian era is just starting.
More in our Research and Productivity categories — and see what agents are doing to code in Claude Code vs Cursor.
