If you have been clinging to your Arc browser because nothing else quite captures that sidebar magic, OpenAI just gave you a very compelling reason to reconsider.

In a significant update to ChatGPT Atlas—the standalone AI browser OpenAI launched for macOS just last month—the company has introduced vertical tabs. The update brings a distinct visual flair that will feel immediately familiar to fans of The Browser Company’s “classic” Arc interface, signaling that OpenAI is serious about competing not just on intelligence, but on user interface design too.

The headline feature here is unmistakable. Instead of the traditional horizontal tab strip cluttering the top of your window, you can now banish your tabs to a collapsible left-hand sidebar. This utilizes the “widescreen” reality of modern displays, where vertical space is at a premium but horizontal space is abundant.

Similar to Arc, the new Atlas sidebar allows you to resize the panel and reorder tabs with a fluid drag-and-drop motion. However, it’s not a 1:1 clone. While Arc revolutionized the browser by merging the address bar and tabs into a single sidebar entity, ChatGPT Atlas has taken a hybrid approach. The address bar remains firmly planted at the top of the screen, creating a “T-shaped” UI layout when vertical tabs are active.

It’s a design choice that might annoy purists who want a completely clean top border, but it retains the familiarity of Chrome or Safari while offering the organizational benefits of a sidebar. To activate it, users can simply right-click inside the address bar, hover over the new “Tab Style” menu, and select “Vertical Tabs.”

Perhaps the most pragmatic—and ironic—update is the new ability to set Google as your default search engine.

When ChatGPT Atlas launched in October, the premise was a “browser that browses for you,” relying heavily on its internal AI to synthesize answers from the web. But as any power user knows, sometimes you don’t want a synthesis; you just want to find a specific Reddit thread or a direct link to a documentation page.

Allowing users to default to Google is a tacit admission that the “AI-only” browsing experience isn’t quite ready to replace the traditional search index entirely. It solves the friction of what users have jokingly called “Googling with extra steps.” Now, if Atlas’s AI summary isn’t what you need, a familiar list of blue links is just a click away, or available immediately if you tweak your settings.

Beyond the visual overhaul, OpenAI has padded this update with several quality-of-life improvements that suggest Atlas is maturing quickly from a “tech demo” to a daily driver:

• Multi-select tabs: You can now hold down Command or Shift to select multiple tabs at once. This is crucial for mass-closing research rabbit holes or moving groups of tabs to new windows.
• Extension import: For those hesitant to switch because of their meticulously curated extensions, Atlas now supports importing extensions directly from your existing default browser during the initial setup. (Note: This appears to be for new installations only at the moment, with a patch likely coming for existing users.)
• iCloud Keychain support: The browser now plays nicely with Apple’s native password manager, supporting passkeys via iCloud Keychain.

The 2025 AI browser wars

This update comes at a pivotal moment in the “AI Browser Wars” of 2025. Since The Browser Company “froze” the classic Arc browser back in May to focus on their new Dia project, there has been a gap in the market for a stable, sidebar-centric browser that isn’t purely experimental.

OpenAI seems eager to fill that void. With Perplexity’s Comet browser gaining traction among researchers for its “deep search” capabilities, and Google aggressively rolling out Gemini features directly into Chrome, Atlas has to fight on two fronts: it needs to be smarter than Chrome and better designed than Comet.

Adopting vertical tabs—a feature beloved by power users but historically ignored by mainstream browsers like Chrome (until recently)—is a smart play. It positions ChatGPT Atlas not just as an “AI tool,” but as a legitimate, ergonomic workspace for managing the dozens of tabs we all inevitably hoard.

The update is rolling out now to ChatGPT Atlas users on macOS. You can check for the update via the generic “Check for Updates” mechanism in the app menu, or verify the changes on the official OpenAI changelog.