By Kshetez Vinayak, founder of SupaSidebar. Last updated May 7, 2026.
TL;DR:
Dia is The Browser Company's official Arc successor, owned by Atlassian since October 2025. As of May 2026, Dia has added Arc's sidebar, vertical tabs, and pinned tabs - but it does not have Arc's Spaces or original Cmd+T command bar (replaced by an AI chat interface). For Arc refugees, Dia is one path forward but it inherits the same "all your eggs in one browser" risk that ended Arc. SupaSidebar takes a different approach: it adds Arc's sidebar workflow to whatever browser you already use - including Dia itself - and imports Arc data in 3 clicks. The strongest setup runs both: Dia for AI-first browsing, SupaSidebar on top for Spaces and cross-browser organization.
Quick navigation:
- Want the structured feature-by-feature comparison? → Dia Browser vs SupaSidebar comparison page
- Comparing every Arc alternative? → Arc Browser alternative guide
- Just want to know if Arc is dead? → Is Arc Browser Dead?
- Already decided to leave Arc? → Switching from Arc Browser
The honest framing this post is about to walk through
When The Browser Company put Arc into maintenance mode in May 2025 and pivoted the team to Dia, the company message was clear: Dia is what comes next. After Atlassian completed the acquisition for $610 million in October 2025, that direction got real funding behind it.
But "what comes next" is not the same as "what Arc was." Dia is genuinely good at what it tries to do. It is just trying to do something different.
I have used both Arc and Dia, and I build SupaSidebar - a Mac sidebar app for Arc refugees. So my view is not neutral. The byline above is the disclosure. What follows is my honest take on whether Dia is actually the Arc replacement you want.
What Dia Browser actually is in May 2026
Dia is a Chromium-based web browser developed by The Browser Company, now an Atlassian subsidiary. Dia v1.0.1 reached general availability on macOS on October 8, 2025 (covered by MacRumors the next day), after a private beta that ran from June 2025. Atlassian completed the $610 million acquisition on October 21, 2025.
The core philosophy is "AI-first browsing." Dia is built around a conversational AI assistant that lives in the sidebar. The assistant can read your open tabs, draft replies, summarize pages, and generate context across your tools. That is the design center.
What most "Arc vs Dia" articles miss is how fast Dia has filled in Arc-style features since launch. Vertical tabs and sidebar mode shipped in the v1.x line in October 2025. Focus Mode landed in v1.3.1 (October 29, 2025). Gmail and Google Calendar integrations shipped in v1.1.0 (October 15, 2025). Slack search arrived in v1.6.0 (November 19, 2025). Tab Groups proper shipped in v1.9.0 (December 10, 2025), with Tab Groups for Meetings - which auto-organize calendar tabs into a meeting-specific group - in v1.14.0 (January 14, 2026). TechCrunch covered the cumulative direction in November as "Dia adopting Arc's greatest hits." So if your last impression of Dia was "AI box, no Arc features," that framing is six months out of date.
Per Dia's download page, Dia is "currently available on Apple macOS 14+ with M1 chips or later" - M1 through M4 only, no Intel Macs. The same page confirms Dia is "currently only available on macOS" with a Windows waitlist that has not shipped a release as of May 2026. SupaSidebar ships a universal binary, so it runs on macOS 14+ on either Intel or Apple Silicon - which means an Intel Mac on macOS 14 can run SupaSidebar but cannot run Dia at all. Hardware is one place these two products genuinely differ.
Arc vs Dia vs SupaSidebar at a glance
The full structured table lives on the Dia vs SupaSidebar comparison page. For this post, the four lines that actually decide the choice for Arc refugees:
| Decision factor | Arc (frozen) | Dia | SupaSidebar |
|---|---|---|---|
| Sidebar with pinned tabs | Yes (original) | Yes (pinned tabs grid, sidebar mode) | Yes (Pinned Items + Folders + Smart Folders + Live Tabs) |
| Arc-style Spaces | Yes | No (uses profiles in separate windows) | Yes (with iCloud sync, no account) |
| Cmd+T command bar | Yes (fuzzy search) | No (replaced with AI chat) | Command Panel ⌘⌃K (cross-browser search, 7 scopes, Ask AI) |
| Direct Arc data import | N/A | No (manual recreation) | Yes (3 clicks: Preferences → Import and Export → Arc → Import) |
| Hardware floor | macOS 13+, Intel + Apple Silicon | macOS 14+, M1 or later only | macOS 14+, Intel or Apple Silicon (universal) |
| Browser independence | No (Arc only) | No (Dia only) | Yes (works with 25+ browsers including Dia) |
| Active development | No (maintenance mode since May 2025) | Yes (Atlassian-funded since Oct 2025) | Yes (indie, monthly releases) |
The pattern: Dia matches Arc on sidebar visuals, drops Spaces and the command bar, and adds new hardware constraints (Apple Silicon only). SupaSidebar keeps the Arc workflow, removes the browser lock-in, and runs on Intel Macs too. Pick based on which trade-off matters more.
What Dia does well, genuinely
I want to start here, because it is easy to write a post about a product you compete with and only describe the gaps. Dia has real strengths.
The AI integration is well-executed.
Mornings surfaces your calendar and inbox at the start of the day. The Skills system lets you build custom AI shortcuts in plain English ("help me prioritize my day," "copyedit my Slack post"). The conversational assistant reads context across your open tabs in a way that no Chrome extension I have used does. If your day is "land in browser, deal with knowledge work, leave," Dia's AI is a productivity boost.
The integrations are useful.
Slack, Gmail, and Google Calendar are wired into the AI assistant as first-class tools. Notion content is readable as context (Dia's scraping handles Notion pages and attachments) but isn't a wired-up tool the way Gmail or Slack are. You can ask "what is on my calendar today and what messages am I behind on" and get a real answer. That is genuine new ground for a browser.
The sidebar implementation works.
The pinned-tab grid is a smart compression of Arc's pinned tab pattern. Vertical tabs and focus mode round out the core of what Arc users came for visually.
Atlassian funding gives Dia runway Arc never had.
This matters for long-term users. Arc died partly because The Browser Company could not find a sustainable business model. Dia has Atlassian's enterprise distribution and balance sheet behind it.
End-to-end encrypted Sync is a meaningful privacy upgrade
over the default sync model in many browsers.
Be honest with yourself about which of these features you actually use, though. Most of Dia's real differentiation lives in the AI layer. If you do not want AI as the central feature of your browser, the rest of Dia is "Chromium with a sidebar."
Where Dia falls short of Arc, and what that means for you
This is the part most "Dia is the Arc replacement" articles do not engage with. Dia kept some Arc features. It dropped or replaced others. The gaps are specific.
No Arc-style Spaces.
This is the biggest one. Arc's Spaces were named, persistent browsing contexts - Work, Personal, Research, Project A - each with their own pinned tabs, theme, history, and cookies. One-click switching, no profile-juggling. Dia uses profiles instead, and profiles open in separate windows. If you organized your Arc workflow with 4-6 Spaces, Dia's profiles do not replicate that smoothly. You are running multiple Dia windows.
No Cmd+T command bar.
Arc's command bar was a fuzzy-search launcher across tabs, bookmarks, history, and actions. Keyboard-first. Fast. Dia replaced this with an AI chat interface. The chat is good for "summarize the article in tab 4" but it is a different tool entirely from the speed of fuzzy search. Many Arc power users miss the keyboard launcher more than they miss the sidebar.
No direct Arc data import.
As of May 2026, Dia does not import Arc's StorableSidebar.json. You manually recreate your structure. Given that Dia does not have Spaces anyway, "import" would mean importing pinned tabs and bookmarks - and even that is not built.
No Boosts and no Easels.
Boosts (per-site CSS injection) was a browser-engine feature Arc had. Easels (visual whiteboards) was a separate Arc feature. Both are gone in Dia. SupaSidebar cannot replicate these either - they are the two genuine Arc capabilities that have no equivalent in any other tool I have shipped or seen. Worth being clear about.
Browser lock-in risk.
This is the philosophical issue. Arc users learned the hard way that putting an entire workflow into one browser is risky - when the browser is sunset, the workflow goes with it. Dia is owned by Atlassian, but the same lock-in dynamic applies. If Atlassian's strategic priorities shift in 2027 or 2028, Dia could face the same fate Arc did. The Browser Company's Letter to Arc Members is exactly the kind of letter Atlassian can write next.
The hidden choice: switch browsers or switch strategies
Most "Arc alternatives" articles assume the only question is "which browser do I switch to." That is the same trap that locked you into Arc.
The other choice is: stop putting your entire workflow into one browser. Use whichever browser you want for actual web browsing - Safari, Chrome, Firefox, Brave, even Dia itself - and add a separate sidebar layer that gives you Arc's organization without the lock-in.
That is the SupaSidebar approach. SSB is a Mac sidebar app, not a browser. It works with 25+ browsers including Dia. Your sidebar persists across browsers. If a browser dies, you keep your data and switch.
I built SupaSidebar because I was one of those Arc users who could not find a replacement for the sidebar workflow. After watching Arc go into maintenance mode, my decision was: do not bet my workflow on another single browser. Build the sidebar as a separate layer.
A few specifics that are different from Dia:
- 3-click Arc import: Preferences → Import and Export → Arc → Import. Spaces, links, folders, organization transfer in seconds.
- Works with 25+ browsers in total, including Dia. So you can run Dia AND SupaSidebar together if you want both.
- Arc-style Spaces with iCloud sync, no account required.
- Command Panel (⌘⌃K) - cross-browser search, Air Traffic Control routing, 7 search scopes, and an Ask AI mode. Closer to Arc's Cmd+T than Dia's AI chat is.
For a side-by-side feature table, the Dia Browser vs SupaSidebar comparison page is the structured version of this post.
Honest recommendation: when Dia wins, when SupaSidebar wins, when both wins
The honest answer for most Arc refugees is "use both." Dia handles the in-page AI experience, SupaSidebar handles the sidebar workflow Arc users actually built around. They are not in the same category.
Choose Dia only if:
- AI is the central feature you want from a browser, not a side feature
- You live in Slack, Gmail, and Calendar (and want Notion content surfaced as context) and want those tools deeply integrated into browsing
- You are okay with browser lock-in and trust Atlassian's roadmap
- You did not build your Arc workflow around Spaces and the Cmd+T command bar
- You are okay manually recreating your Arc structure (no direct import)
Choose SupaSidebar only if:
- You want Arc's sidebar workflow without committing to a specific browser
- You are happy with Safari, Chrome, Firefox, Brave, Vivaldi, or Zen for web browsing
- You want direct Arc data import in 3 clicks
- You want real Arc-style Spaces (not profiles in separate windows)
- Indie tools without enterprise-acquisition risk matter to you
Use both (recommended):
- SupaSidebar treats Dia as one of its 27 supported browsers. Run Dia for AI-first browsing inside the page; add SSB on top for Spaces, the Command Panel, Air Traffic Control routing, and Arc data import.
- Your Arc data lives in SupaSidebar. If Dia's strategic direction shifts in 2027 or 2028, your sidebar moves with you - the lock-in problem that ended Arc does not repeat.
- This is the strongest Arc replacement available today: AI-first browsing and Arc-style organization, in two products that compose cleanly.
Why I built SupaSidebar instead of switching to Dia
When Arc went into maintenance mode, I had two choices: wait for Dia, or build the thing I actually wanted. Dia was not the answer for me because I did not want to bet my workflow on another single browser. I wanted my sidebar to outlive whatever browser I was using.
SupaSidebar is what I built. It is a Mac app that gives you Arc's sidebar across any browser. If I switch browsers tomorrow, my sidebar comes with me. That is the part Arc taught me, and the part Dia has not solved.
If you are running Arc on maintenance mode, it will keep working for a while. But if you are ready to move on without losing the sidebar workflow, SupaSidebar has a free version. It is a native Mac app built in Swift, so it is fast, integrates with macOS natively, and syncs across Macs via iCloud with no account required.
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 25+ browsers including Safari, Chrome, Firefox, Arc, Zen, Vivaldi, Brave, Helium, and Dia. It is the closest 1-to-1 replacement for the Arc workflow that does not require switching browsers, and it imports Arc data in 3 clicks.
For the structured Dia vs SSB feature comparison, see /compare/dia-browser. For the full Arc alternatives landscape, see the Arc Browser alternative guide. For the migration playbook, see Switching from Arc Browser. For the Arc status and timeline, see Is Arc Browser Dead?.
The bottom line
Dia and SupaSidebar are not really competitors. Dia is a browser with AI inside it. SupaSidebar is a sidebar layer that runs on top of any browser, including Dia. The framing of "which one replaces Arc" assumes you have to pick a single product to fill the Arc-shaped hole, but that framing is what got Arc users locked in last time.
If your Arc workflow lived in Spaces and the Cmd+T command bar, Dia alone is not a 1:1 replacement and never will be - Dia chose a different design center, and that is fine. The strongest setup for an Arc refugee in May 2026 is to run both: Dia for AI-first browsing inside the page, and SupaSidebar on top for Arc-style Spaces, the Command Panel, and 3-click Arc data import. Your sidebar then survives whatever happens to Dia next.
If you only want one tool, pick the one that matches what you actually used Arc for: Dia if Arc's AI-future direction was your appeal, SupaSidebar if Arc's sidebar-and-Spaces workflow was your appeal. Either way, do not bet your entire workflow on a single browser again.
Frequently Asked Questions
Is Dia Browser a direct replacement for Arc?
Not directly. Dia ships an Arc-style sidebar with vertical and pinned tabs from launch (October 2025), but does not have Arc's Spaces or original Cmd+T command bar. Dia replaces those with profiles and an AI chat interface respectively. For users who valued Spaces and the command bar, Dia is a different product, not a 1:1 replacement.
What are the Mac requirements for Dia and SupaSidebar?
Dia requires macOS 14 or later AND Apple Silicon (M1, M2, M3, or M4). Per Dia's official download page, Dia is "currently available on Apple macOS 14+ with M1 chips or later" - Intel Macs cannot run it. SupaSidebar ships as a universal binary, so it runs on macOS 14+ on either Intel or Apple Silicon. If your Mac is Intel-based, SupaSidebar is the only option of the two.
Can I import my Arc sidebar into Dia?
As of May 2026, Dia does not support direct import of Arc's StorableSidebar.json. You would need to manually recreate your structure. SupaSidebar imports Arc data directly in 3 clicks (Preferences → Import and Export → Arc → Import). Spaces, links, folders, and organization transfer in seconds.
Will Dia eventually have Spaces?
Possibly. Dia has been adding Arc-style features incrementally - pinned-tab refinements in November 2025 (v1.4.0), Tab Groups in December 2025 (v1.9.0), Tab Groups for Meetings in January 2026 (v1.14.0). Spaces could come in a future update. But as of May 2026, Spaces are not on the public roadmap and Dia uses profiles as its workspace concept instead.
Is Dia better than Arc was?
Different. Dia is better at AI-first browsing and integrations with productivity tools (Slack, Gmail, Calendar; Notion content can be read as context but isn't a wired-up tool). Arc was better at the keyboard-driven, Spaces-organized workflow that power users built around. The right answer depends on what you used Arc for.
Can I use SupaSidebar with Dia?
Yes. SupaSidebar supports 25+ browsers including Dia. You can use Dia as your browser and add SSB on top for Spaces, cross-browser tab access, and Arc data import. This is the "use both" path for Arc refugees who want Dia's AI features and SupaSidebar's organization layer.
What is the safest long-term Arc replacement?
For independence from any single browser's lifecycle: SupaSidebar (works with 25+ browsers, your sidebar survives browser switches). For betting on Atlassian's roadmap and AI-first browsing: Dia. For Arc's own survival: keep using Arc until it stops working - it is still in maintenance mode as of May 2026, not sunset.