Arc was once a dazzling but overly ambitious experiment in the evolution of web browsers, and now its "soul" is being reborn in a more powerful successor. The new AI browser called Dia is drawing inspiration from the "failures" of its predecessor, Arc. Josh Miller, founder of The Browser Company, confirmed on Sunday that this new browser will bring Arc's greatest features—such as the iconic sidebar mode—into Dia, integrating them deeply with AI-native memory and agent capabilities.

This strategic move is significant. After The Browser Company was acquired by Atlassian for an astonishing $610 million, Dia's development roadmap has become crystal clear. It suggests that Dia may have a head start in the fierce competition for AI browsers, as it is not starting from scratch but building on the valuable experience and user insights gained from developing Arc for over a year.

Looking back at the launch of Arc in mid-2023, it was hailed as a complete reimagining of modern internet usage. It offered independent workspaces (Spaces) for work and personal browsing, fixed tabs, a command bar similar to Apple's Spotlight search, and a powerful sidebar that integrated search, tag lists, bookmarks, and audio controls.

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However, Arc may have gone too far in its pursuit of innovation. Miller later admitted that Arc ultimately became "too complex" for most people. In a blog post earlier this year, he reflected that Arc was simply too different, with too much to learn and not enough reward. More importantly, Arc lacked cohesion in its core functions and values. Its experimental nature was part of its charm, but also brought complexity. This reflection eventually led the company to decide to gradually stop developing Arc and open-source it, focusing all their efforts on building Dia instead.

But the exploration of Arc was far from a complete failure. Even though it did not become a widely adopted consumer product, it provided the company with over a year of deep insights, helping them understand which modern browser features truly resonated with users, and which did not.

These valuable experiences are giving Dia a head start in building its feature set. As Miller stated in a post on X, Dia's architecture is significantly better in terms of AI, speed, and security, but it will introduce features beloved by Arc fans. Among them, the sidebar mode was recently discovered in the latest "early bird" version of the Dia AI browser.

In fact, Dia has already begun "recreating" Arc's "great works." A long-time Arc user and now a Dia early access participant said he is "almost no longer missing Arc," because Dia now has focus mode, vertical tabs, grid view for fixed tabs, and automatic picture-in-picture playback of Google Meet when switching tabs. Miller also hinted that the team is exploring how to transition Arc's iconic "Spaces"—browsing areas with independent fixed tabs, collections, themes, and history—to Dia. The team is currently testing the fixed tab feature.

Miller is also actively seeking user feedback to determine which other features to add, such as sliding profiles, and updates inspired by Arc Search for the upcoming Dia mobile app in 2026. He emphasized that Dia will be less bloated and achieve AI-native capabilities in memory and agent features.

After being acquired by Atlassian, The Browser Company will continue to operate independently. Miller said this will allow the company to add more "browser foundational features" (the favorites of Arc fans) to the Dia browser, while, supported by its new owner, Dia is also developing deeper integrations with Atlassian's Jira and popular applications like Linear.