Atlas Is Gone — Here's What 3 Million Users Switched To

Now that ChatGPT Atlas has officially shut down, the real question is what to actually install next. The market answered that question faster than OpenAI expected — there are now three genuinely different approaches to AI-assisted browsing, not just one obvious replacement. Here's an honest comparison of the three most-recommended options, including the trade-offs each one doesn't put on its own homepage. This isn't a "10 AI browsers ranked" listicle. It's three specific, meaningfully different tools — pick based on what you actually did in Atlas, not on which one has the flashiest landing page.

Quick Verdict

Option 1: OpenAI's Own ChatGPT Chrome Extension

This is the most literal replacement for Atlas, because it is OpenAI's replacement for Atlas. Announced the same day as the shutdown, the extension reads the page you're currently viewing and lets you ask questions, get summaries, or start longer tasks — the exact core feature Atlas users relied on, just delivered inside Chrome instead of a separate browser.

The honest catch: as of the announcement, the rollout is gradual and gated — OpenAI's own help documentation says availability depends on your plan, region, device, and workspace settings, and work/school accounts may need an admin to turn it on. If you go looking for it today and don't see it yet, that's expected, not a bug on your end.

• Pros: No new browser to learn, keeps your existing Chrome bookmarks/extensions/passwords intact, chats sync with your regular ChatGPT account and app.
• Cons: Not universally available yet, and heavier agentic tasks (the kind Atlas's "agent mode" handled) are being routed to the separate ChatGPT desktop app and a cloud-based browser instead — meaning some Atlas power-user features aren't a one-to-one match inside the extension itself.

Option 2: Perplexity Comet

Comet is a full standalone browser (not an extension), built by Perplexity around its citation-based answer engine. It launched in mid-2025 as a $200/month product gated behind Perplexity's top subscription tier, then went free on every major platform in March 2026 — which is a large part of why it's the most recommended Atlas alternative right now.

The free tier includes agentic search, page summarization, voice mode, shopping assistance, and Perplexity's Deep Research feature, all built into the browser itself. Where it gets gated is autonomous, multi-step agent tasks — form fills, purchases, email drafting — which draw from a credit allowance that's noticeably limited on the free plan.

• Pros: Genuinely free with real functionality, not a crippled trial; citation-based answers are useful for anyone doing research-heavy browsing; available on Mac, Windows, iOS, and Android.
• Cons: Two things worth knowing before you commit: Perplexity's own CEO has publicly discussed using browser data to build advertising profiles, and independent security researchers flagged a prompt-injection vulnerability (dubbed "CometJacking") that could expose connected account data through a malicious link. Neither is disqualifying, but both are worth factoring in if privacy or security is a priority for how you browse.

Option 3: Sigma Browser

Sigma takes a different approach entirely — instead of routing your requests to a cloud AI model, its "Sigma Eclipse" architecture runs AI tasks directly on your device, which means it can work offline and keeps your browsing data off external servers. It includes AI chat, content generation, article summarization, and an integrated AI agent, positioned specifically around privacy and speed rather than research depth.

A caveat worth flagging directly: sources disagree on platform availability and pricing for Sigma Browser — some listings describe it as available on Mac and Windows with mobile apps via the App Store and Google Play, while at least one independent review describes it as currently macOS-exclusive. Given the conflicting information, confirm current platform support and pricing tiers directly on sigmabrowser.com before choosing it as your main Atlas replacement, especially if you're not on a Mac.

• Pros: On-device processing is a genuinely different privacy model than cloud-based competitors; core AI chat features are free with no account required for basics.
• Cons: Smaller company, less third-party review coverage than Comet, and the platform-availability confusion above means you should verify before switching your daily browser.

Which One Should You Actually Pick?

• If you mostly used Atlas for quick page summaries and Q&A and don't want to learn a new browser: wait for the ChatGPT Chrome extension to reach your account, and keep using Chrome in the meantime.
• If you did research-heavy work in Atlas — comparing sources, fact-checking, long reading sessions: Perplexity Comet is the closest match, with the caveat that you should review its data-collection model first.
• If privacy was your main reason for being cautious about AI browsers in the first place: Sigma Browser is the only option here that keeps AI processing on your own device, provided it actually supports your platform.

None of these three is a perfect Atlas clone — and that's arguably the more important lesson from this whole cycle. As covered in our look at Google's Agentic Browsing category in Lighthouse, AI-assisted browsing is still a genuinely young category where the leading tools disagree on the basics — cloud vs. on-device processing, standalone browser vs. extension, free vs. subscription-gated automation. Expect more churn like the Atlas shutdown before this space settles down.

Frequently Asked Questions

Q1. Do I have to pick just one?

No — the ChatGPT Chrome extension runs inside Chrome and doesn't require switching your default browser, so you can pair it with Comet or Sigma as your main browser if you want both.

Q2. Will my Atlas bookmarks work in any of these?

Only if you exported them as an HTML file before the shutdown — all three options here support standard bookmark imports, but none of them recover Atlas data after the fact.

Q3. Is any of these as good as Atlas was at agent tasks (bookings, purchases, form-filling)?

Comet's Max tier and OpenAI's upgraded ChatGPT desktop app both target this use case directly; the free tiers of every option here are noticeably more limited for autonomous multi-step tasks than what Atlas's paid agent mode offered.

The Bottom Line

There's no single "best" Atlas replacement — which browser fits depends entirely on whether you valued Atlas for quick assistance, deep research, or privacy-first automation. For most people who just want the least disruptive switch, OpenAI's own Chrome extension is the logical default once it's available on your account. For anyone who wants a fuller standalone browser today, Comet's free tier is the most tested and widely reviewed option, with Sigma as the privacy-first alternative worth checking once you've confirmed it supports your platform.