Rio vs Dia
Rio is a free, open-source Chromium browser for Mac that keeps Arc's spaces as spaces, each with its own pinned tabs, folders and Today tabs. It needs no account and imports your Arc setup in one step. Dia needs an account and is closed source, and Arc's guide to Dia says your spaces become profiles.
Side by side
| Rio | Dia | |
|---|---|---|
| Made by | Levon Adamyan, independent | The Browser Company, part of Atlassian since October 2025 |
| Sidebar | Spaces with pinned tabs, folders, favorites and Today tabs | Optional, sidebar or top tabs; Arc's spaces import as profiles, folders as tab groups |
| Chrome Web Store extensions | Yes | Yes |
| Side panel extensions | Yes | Yes, since Dia 1.10.1 (December 2025) |
| Account | Not needed | Required |
| Open source | Yes, GPL-3.0 | No |
| Speedometer 3.1, Chrome = 100 | 97.8, our run on one Mac | 89.3 from BrowseRating's scores; 93.5 and 91.7 from runs in Aside's post; each on another Mac |
Where Rio is ahead
- Arc's sidebar, as it was. Rio keeps spaces as spaces, each with its own pinned tabs, folders and Today tabs. Arc's guide to Dia says your spaces become profiles and your folders become tab groups.
- No account. Rio runs without signing in. Dia needs an account.
- Open source. Rio's code is on GitHub under GPL-3.0, so anyone can read it and build it. Dia is closed source.
- Speedometer 3.1. Rio scored 97.8 against Chrome on our Mac. BrowseRating's scores put Dia at 89.3% of its Chrome score, and runs in Aside's post put it at 93.5% and 91.7%, each on a different Mac. We have not run Dia's Speedometer ourselves.
Who Rio is for
People who want Arc's spaces kept as spaces, no account, and code they can read.
Questions
How does Dia bring over Arc's spaces?
Arc's guide to Dia says Arc spaces become Dia profiles and folders become tab groups. Rio brings Arc's spaces over as spaces, with their pinned tabs, folders and favorites.
Is Dia open source?
No. TechCrunch reports that Arc and Dia are both built on The Browser Company's Arc Development Kit, which the company keeps closed, and that this is why Arc has not been open-sourced. Rio is open source under GPL-3.0.
Do I need an account for Rio?
No. Rio runs without signing in to anything. Dia needs an account.
Which is faster, Rio or Dia?
Rio scored 97.8 on Speedometer 3.1 against Chrome on our Mac. BrowseRating's scores put Dia at 89.3% of its Chrome score, and runs in Aside's post put it at 93.5% and 91.7%, each on a different Mac.
Sources
- Arc Help Center, Move from Arc to Dia (October 22, 2026)
- Arc Help Center, Arc sunset FAQ (October 22, 2026)
- Dia changelog
- Dia changelog 1.10.1: side panel extensions render in Dia (December 18, 2025)
- TechCrunch, Arc browser sunsets December 22 (October 22, 2026)
- Atlassian, Atlassian completes acquisition of The Browser Company of New York (October 21, 2025)
- BrowseRating, macOS ARM Speedometer 3.1 rankings (October 3, 2026)
- Aside, What Speedometer 3.1 actually measured (August 14, 2026)
- Rio releases on GitHub
