Arc shutting down: Zen, the open source alternative

On 22 October The Browser Company announced that Arc will stop working on 22 December 2026. New accounts can no longer be created, and in two months the desktop app for macOS and Windows shuts down, accounts are deactivated and personal data is deleted within thirty days.

Plenty of us at Quinck used Arc: for some it had been their work browser for years. We loved it for as long as we could. But looked at closely, this news is not a bolt from the blue. It had been on the cards for at least a year and a half, and from the company's point of view it makes perfect sense. Below we explain why, and which Arc alternative we use: Zen Browser, open source and built on Firefox.

In 30 seconds

Arc shuts down on 22 December 2026. On 23 November Arc Search on iOS and Android loses its AI features, sign-in and tab sync. The Browser Company points users to Dia, its AI browser, as the successor.
It was predictable. Arc stopped getting new features in May 2025, and in September 2025 Atlassian bought the company for 610 million dollars, betting on Dia. Keeping two browsers secure costs too much.
We're moving to Zen. It's an open source browser built on Firefox, with the Arc ideas we liked: vertical tabs, workspaces, split view. And it doesn't depend on the choices of a single company.

What The Browser Company announced

The shutdown happens in three steps:

right away: new Arc accounts can no longer be created;
23 November 2026: Arc Search for iOS and Android loses its AI features (including "Browse for Me"), account sign-in and tab sync;
22 December 2026: Arc for macOS and Windows stops working, accounts are deactivated and related data is deleted within thirty days.

The official reason is security. Keeping a browser secure, the company writes, takes constant, dedicated work that only grows in the age of AI. Dia was built from scratch on today's security standards, so the engineering and security teams will focus there. Anyone who wants to stay in the family can bring bookmarks, passwords, extensions, history, spaces and tab groups into Dia.

Why it was predictable

Anyone following Arc closely had seen every signal.

May 2025, the feature freeze. In a letter to users, CEO Josh Miller explained that Arc would not grow any further. People who tried it tended to stay, but usage looked like that of a tool for professionals, not a mass-market product: features like Spaces or Live Folders were used by few. Arc was simply too different: too many new things to learn for a benefit that wasn't enough for most. The letter called it the "novelty tax". From then on Arc only received Chromium updates and security fixes.

September 2025, the acquisition. Atlassian bought The Browser Company for about 610 million dollars in cash, with the stated goal of rethinking the browser for work in the age of AI and connecting Dia to products such as Jira and Trello. Arc had no place in that plan.

A product in maintenance doesn't stay in maintenance forever. A browser in "maintenance mode" is not a static object. Chromium ships a new version every four weeks, zero-day vulnerabilities keep coming, and every update has to be integrated and tested on a codebase nobody is evolving any more. It's a fixed cost with no return.

Why it makes sense for the company

Seen from the inside, the choice is almost forced. Two browsers mean two codebases to keep in step with Chromium, two attack surfaces to guard, two products to support. With AI agents inside the browser the problem grows further: a browser that reads pages and acts on your behalf is exposed to new risks, such as prompt injection, and needs security work that can't be done halfway.

When a company has one product that has stopped growing and another it has bet its future on (and that a buyer has put 610 million into), focusing its people on the latter is the rational decision. We build and maintain software every day, so we know it well: every product in production has a maintenance cost, even when nobody is working on it. Sooner or later someone has to decide whether to pay it.

That said, what leaves a slightly bitter taste is something else. Arc was a closed product: when the company behind it stops believing in it, its users have no option but to leave. It's the same reason why, when it makes sense, we prefer open source.

Zen Browser, our Arc alternative

And this is where Zen comes in. Many of us have already switched, and we've become fans.

Zen Browser is a free and open source browser, released under the Mozilla Public License 2.0, born in July 2024 as a fork of Firefox. It runs on macOS, Windows and Linux. Unlike Arc and Dia it doesn't use Chromium but Gecko, Firefox's engine: a small contribution to a web that doesn't depend on a single engine.

What people coming from Arc will find:

vertical tabs in a sidebar, on the left or right, with a compact mode that hides it when you don't need it;
workspaces, the equivalent of Spaces, each with its own pinned tabs;
Split View, to put several tabs side by side in the same window;
Glance, which opens a link in a preview over the page instead of a new tab (similar to Little Arc);
tab folders, nested too;
Zen Mods, themes and tweaks made by the community.

Extensions are installed from the Firefox store, which works just like Chrome's: almost all the popular ones are there. Sync with a Mozilla account works too.

In fairness, we should mention the limits too. Versions still carry the "b" suffix for beta, some sites built only for Chrome can cause the odd problem, and a few Chrome-only extensions are missing. In our case the only one was Claude's, which the Claude desktop app has made unnecessary anyway. For everyday use, in our experience, this hasn't been an obstacle.

How to move from Arc to Zen Browser

You have until 22 December, but it's better not to leave it to the last day.

Update Arc to the latest version, which adds the option to export your data from the browser.
Save passwords and bookmarks. Passwords are best exported into a password manager, if you don't use one already: this is the right moment to start.
Install Zen from the official site and import the bookmarks from the file you exported from Arc.
Rebuild your workspaces. Arc's pinned tabs arrive in Zen as bookmarks, not pins. Community tools such as arc2zen turn them into pinned tabs in the right workspaces: back up your profile before using them.

The rest is habit: after a couple of days Zen's sidebar already feels at home.

Zen or Dia: which Arc alternative to choose

Anyone leaving Arc has two paths: follow The Browser Company to Dia, or switch families. The main differences:

	Zen Browser	Dia
Engine	Gecko (Firefox)	Chromium
Code	Open source, MPL 2.0 licence	Proprietary
Development	Open source community	The Browser Company (Atlassian)
AI	Not built in, via extensions	At the core of the product
Import from Arc	Community tools	Built in
Linux	Yes	No

Dia is the convenient choice: the import is complete and the interface is from the same family. Zen is the choice that doesn't tie you to a single company: if the project changed direction tomorrow, the code would still be there and someone could carry it on. After Arc, for us that argument weighs more than convenience.

Frequently asked questions

When does Arc shut down?

On 22 December 2026 Arc for macOS and Windows stops working and accounts are deactivated. Arc Search for iOS and Android loses its AI features, sign-in and sync on 23 November 2026.

Why is The Browser Company shutting down Arc?

To focus engineering and security on Dia, its AI browser. The company explains that keeping a browser secure takes constant work, which grows with AI. Arc had stopped receiving new features back in May 2025.

What is Zen Browser?

A free and open source browser built on Firefox, under the MPL 2.0 licence, available for macOS, Windows and Linux. It takes many ideas from Arc: vertical tabs, workspaces, Split View and link previews.

Is Zen a good replacement for Arc?

For us, yes. It offers the workflow we were used to with Arc, it's open source and it doesn't depend on the decisions of a single company. It still has a few early-stage limits, and extensions come from the Firefox store, where almost all of them are available.

What is the best Arc alternative?

It depends on what you're after. Dia is the official successor, with a complete import and AI features. Zen Browser is the open source alternative closest to Arc in interface and workflow, and it's the one we use.

Is Zen Browser safe?

Zen follows Firefox updates, so it gets the same security fixes as the Gecko engine, and its code is public and verifiable. As with any browser, it's best to keep it up to date.

Can pinned tabs be moved from Arc to Zen?

Not with a built-in importer. Pinned tabs arrive as bookmarks; to recreate them as pins in your workspaces there are community tools such as arc2zen, to be used after backing up your profile.