The Browser Company announced Thursday that it will sunset its beloved, design-forward Arc browser on December 22, 2026, herding users toward Dia, its AI-first browser. The stated reason: keeping a browser secure in the age of AI costs too much. "Keeping a browser secure takes constant, dedicated work that is only increasing in the age of AI," the company wrote, adding that "Dia was built from the ground up to meet today's security standards, so that's where our engineering and security teams will focus moving forward."

The wind-down is a three-act tragedy. As of Thursday, new Arc accounts can no longer be created. On November 23, Arc Search on iOS and Android loses its AI features, including "Browse for Me," and users will no longer be able to sign in or sync tabs - though the app will keep functioning as a basic local browser, like a car with the engine removed but the radio still working. On December 22, Arc stops working entirely on Mac and Windows. Accounts will be deactivated, personal data will be deleted within 30 days, and Arc Search will be removed from the Google Play Store.

The Browser Company claims Dia now surpasses Arc in speed, stability, and security benchmarks. Social media reactions were largely disappointed, with many reviving requests for the company to open-source Arc. CEO Josh Miller previously explained why that's not happening: Arc is built on the Arc Development Kit (ADK), a proprietary internal SDK that also powers Dia. Open-sourcing Arc would mean giving away Dia's intellectual property. "While we'd love to open-source Arc someday, we can't do that meaningfully without also open-sourcing ADK," Miller noted. "And ADK is still core to our company's value."

For those making the switch, Dia carries over equivalents of several core Arc features: swipe between work and personal environments via "Profiles" (formerly Arc's Spaces); Arc's signature vertical tabs remain as an optional sidebar layout; and Folders have been rebranded "Pinned Tab Groups." Passwords, bookmarks, extensions, and history transfer seamlessly. Arc features remain free in Dia, with AI optional.

The shutdown closes a chapter that began in 2025, when the startup stopped active feature development on Arc. The Browser Company - acquired by Atlassian for $610 million in 2025 - conceded that while early adopters loved the browser's novel interface, the "novelty tax" and complexity limited mainstream adoption. Arc was fiercely beloved by a dedicated group of enthusiasts, but never became the mass-market Chrome alternative its makers envisioned.