Helium vs Arc Browser (2026): Is the Open-Source Arc-Like Browser Ready?

By Kshetez Vinayak, founder of SupaSidebar. Last updated June 18, 2026.

Helium is the closest open-source Chromium browser to Arc's look, but not to Arc's workflow. As of mid-2026 Helium has vertical tabs and a configurable sidebar, runs on an ungoogled-chromium base, and ships privacy features Arc never had. What it does not have is Arc's full workspace model: Spaces, profile-linked contexts, and a command bar that searches across everything. So the honest answer to "is the open-source Arc-like browser ready" is: ready as a fast, private, minimal browser with vertical tabs, not ready as a one-for-one Arc replacement. If the part of Arc you actually miss is the sidebar-and-Spaces workflow, the most reliable way to keep it is to add that layer on top of whatever browser you run, including Helium, with a sidebar app like SupaSidebar.

Looking for something specific?

• Wondering if Arc is dead and what maintenance mode means? → Is Arc Browser Dead?
• Want every Arc alternative ranked? → Arc Browser Alternative Guide
• Looking specifically for an open-source Arc? → Open-Source Arc Browser

What Helium actually is

Helium is a free, fully open-source web browser from the imputnet project, built on top of ungoogled-chromium. Ungoogled-chromium is a version of Chromium with Google's integrated services, telemetry, and "personalized" hooks stripped out, and Helium adds back the conveniences that bare ungoogled-chromium leaves missing: it ships with uBlock Origin preinstalled and enabled, handles extension updates through a privacy-respecting proxy instead of talking directly to the Web Store, and makes no web requests on first launch.

The positioning is privacy and minimalism, not feature maximalism. Helium markets itself as a browser "made for people," with native !bangs (more than 13,000 offline-ready shortcuts that jump straight to a site or an AI tool), a built-in split view, and a deliberately quiet interface with no crypto wallet, no opinionated AI assistant, and no bloat. Reviewers who have run it as a daily driver describe it as a genuinely fast, lightweight Chrome alternative, with the tradeoff that it trails Brave, Chromium, or Vivaldi on DRM media playback and multi-device sync (Tech2Geek review).

The reason Helium keeps coming up in Arc conversations is recent: it shipped vertical tabs. Helium 0.9.1.1 rolled out an experimental vertical-tabs layout, and follow-up updates added the ability to position vertical tabs on the right side and to save sidebar width and collapse preferences across sessions (Neowin). Users can now pick between three layouts: classic, compact, and vertical. That vertical layout is what makes Helium "look like Arc," and it is what triggered an r/browsers thread titled "Finally, Helium is now looking like Arc" that drew hundreds of upvotes.

What Arc is now

Arc is the browser from The Browser Company that defined the sidebar-and-Spaces aesthetic Helium is being measured against. The catch is timing: Arc is no longer being built. The Browser Company stopped active feature development on Arc in May 2025 and moved its focus to Dia, an AI-first browser, then was acquired by Atlassian for $610M in September 2025 (Android Authority). Arc still downloads, launches, and gets Chromium-based security patches, but no new features are coming. That state is called maintenance mode, and what it means for users is covered in depth in Is Arc Browser Dead?.

So "Helium vs Arc" is partly a comparison between a browser that is actively shipping features and one that has frozen. Helium is gaining vertical tabs and sidebar polish month over month; Arc's feature set is fixed at wherever it stood in mid-2025. That changes the question from "which is better today" to "which has a future," and on that axis Helium is the one still moving.

Sidebar and vertical tabs: close in look, not in depth

Helium's vertical-tabs layout puts your tabs in a column on the side of the window, left or right, and remembers your width and collapse state. That covers the most visible part of what people loved about Arc: tabs on the side instead of crammed across the top. For a lot of Arc refugees, that single change is "the last missing piece," which is exactly how the r/browsers reaction framed it.

But Arc's sidebar was never only a vertical tab strip. It folded in pinned tabs, favorites, a command bar, and the workspace switcher into one persistent panel. Helium's sidebar is a tab strip with a few preferences, not a workspace surface. There is no Spaces model layered on top of it, no notion of switching an entire context (its own tabs, its own pinned set) with one keypress. The look matches; the depth does not.

This is the same gap the open-source Arc question keeps running into. Open-source Chromium browsers can clone Arc's appearance faster than they can clone Arc's full workflow, because the appearance is a layout setting and the workflow is a whole organizing system.

Spaces and workspaces: the real dividing line

Arc's Spaces let you keep separate sets of tabs, pinned items, and a profile per context, so "work" and "personal" are two different sidebars you flip between instantly. That workspace model, not the vertical tabs, is what most heavy Arc users actually structured their day around.

Helium does not have Spaces. It has vertical tabs and a clean window, which is a different thing. If your Arc workflow was "one Space per client, switch contexts in a keystroke," Helium's vertical tabs alone will not reproduce it. This is the single biggest reason "Helium vs Arc" should not end at "they both have side tabs now." For a privacy-first user who kept everything in one window anyway, the gap may not matter. For a multi-context power user, it is the whole ballgame.

If you want Spaces specifically on top of a browser like Helium, that is where a sidebar app comes in, covered below.

Maturity and openness: where Helium clearly wins

On the two axes the open-source crowd cares about most, Helium has the cleaner story.

The honest counterweight: Helium is younger and narrower. The same long-term review that praised its speed and privacy also flagged weaker DRM media support and thinner multi-device sync than mainstream browsers. Helium wins on openness and momentum; it is not yet the most full-featured browser on the list.

Keeping Arc's workflow on Helium (or any browser)

There are two realistic ways to handle the gap between "Helium's vertical tabs" and "Arc's full workspace."

The first is to wait. Helium is actively developed, and a Spaces-style feature could land eventually. That is a bet on a roadmap, with no committed date.

The second is to stop tying the workflow to the browser at all. Keep Helium for its openness, privacy, and speed, and add Arc's sidebar workflow on top of it as a separate layer. That is what SupaSidebar does. SupaSidebar is a macOS app that adds a persistent vertical sidebar, Spaces, a command panel, and pinned items to whatever browser is in front, and Helium is one of the browsers it supports with full Live Tabs. So you get Helium's ungoogled-chromium privacy posture and the Arc-style workspace model at the same time, without waiting for either browser to ship it.

The advantage of the layer approach is that it survives browser churn. Arc froze; Helium is young; Dia is changing weekly. A sidebar that works across all of them means the workflow does not have to be re-learned every time the browser underneath it changes.

Which should you pick?

A scannable read on who lands where:

• If you want maximum privacy and a quiet, fast browser, and side tabs are enough: pick Helium. Its ungoogled-chromium base, preinstalled uBlock Origin, and minimal interface are the point, and the vertical layout covers the visible part of the Arc look.
• If you specifically need open source: pick Helium. Arc is closed source and is not being opened.
• If you want Arc's actual workspace model (Spaces, profile contexts, command bar across everything): Helium alone does not have it, and Arc is in maintenance mode. Add the workspace layer on top with SupaSidebar instead of betting on either browser's roadmap.
• If you are still on Arc and just want to stop losing features: Arc still runs, but nothing new is coming. Pair it with a sidebar app now so your workflow is portable when you do move. See Switching from Arc Browser for the migration path.

Conclusion

Helium is the most credible open-source, Chromium-based answer to "something that looks like Arc," and in 2026 it is genuinely ready as a private, fast, minimal browser with vertical tabs. It is not ready as a full Arc replacement, because Arc's value was the workspace model (Spaces, contexts, a unifying command bar) and Helium has the vertical tabs without that system. Arc itself is no longer a moving target either, since it sits in maintenance mode with no new features planned.

Privacy-first, single-window users: Helium is a strong pick and a better long-term bet than a frozen browser. Open-source purists: Helium, since Arc will not be opened. Workspace-heavy users who structured their day around Arc's Spaces: keep the browser you like, including Helium, and add the sidebar-and-Spaces layer on top with SupaSidebar so the workflow outlives whatever happens to any one browser.

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Why we recommend SupaSidebar

SupaSidebar is a macOS app that brings Arc's sidebar to every browser - one sidebar for tabs, bookmarks, files, and apps across 33 browsers including Safari, Chrome, Firefox, Arc, Brave, Vivaldi, Helium, Comet, and Dia. For anyone comparing Helium and Arc because they want Arc's workflow without Arc's future risk, it solves the real problem: it keeps the persistent vertical sidebar, Spaces, command panel, and pinned items on top of whatever browser already works, including Helium's ungoogled-chromium build. No fork to wait on, no engine to switch. A free version is available.

By Kshetez Vinayak, founder of SupaSidebar. Last updated June 18, 2026.

FAQ

Is Helium a good Arc replacement?

Helium is a good replacement for Arc's look and for users who mainly wanted vertical tabs in a private, fast browser. It is not a full replacement for Arc's workflow, because Helium does not have Arc's Spaces or workspace model. If you want that workflow, pair any browser with a sidebar app like SupaSidebar.

Does Helium have Spaces like Arc?

No. As of mid-2026 Helium has vertical tabs and a configurable sidebar layout, but it does not have Arc-style Spaces or profile-linked workspaces. It is a privacy-focused minimal browser, not a workspace browser.

Is Helium open source and is Arc open source?

Helium is fully open source and built on ungoogled-chromium. Arc is closed source, and The Browser Company has said it does not plan to open-source Arc. If open source is a hard requirement, Helium meets it and Arc does not.

Is Arc still being developed in 2026?

No. Arc entered maintenance mode after The Browser Company stopped active feature development in May 2025 to focus on its newer browser, Dia. Arc still works and gets security patches, but no new features are planned.

Can I use Helium's privacy features and still get Arc's sidebar?

Yes. SupaSidebar is a macOS app that adds an Arc-style sidebar with Spaces, a command panel, and pinned items on top of any of 33 supported browsers, including Helium. You keep Helium's ungoogled-chromium privacy posture and gain the Arc workspace layer at the same time.

Why does Helium suddenly look like Arc?

Helium added an experimental vertical-tabs layout in version 0.9.1.1 and later updates let you position the tabs on the right and save sidebar width and collapse preferences. Vertical tabs are the most visible part of Arc's look, which is why the comparison surfaced in 2026.