Browser comparison
Arc vs Sill: two takes on the sidebar browser
Arc proved a browser could feel like a place — sidebar tabs, Spaces, a command bar. Sill shares that DNA but makes two different bets: native WebKit instead of Chromium, and privacy as architecture instead of policy. Here's an honest look at both, including where Arc's development pause leaves you.
Full disclosure: this studio builds Sill. This is written as the comparison worth reading anyway — Arc's genuine strengths included, its details drawn from its own public documentation.
Arc, from The Browser Company, reimagined what a browser looks like: tabs in a sidebar, Spaces for different contexts, a command bar that makes the keyboard the fastest way around. It earned a devoted following for good reason, and if you love Arc's design, Sill will feel familiar rather than foreign — sidebar, workspaces, ⌘K and all.
The honest context you need first: per The Browser Company's own announcements, new feature development on Arc stopped in 2025 as the team shifted to Dia, its AI browser, and Atlassian announced an agreement to acquire the company later that year. Arc continues to receive security updates as of this writing, but it is, by its maker's description, no longer where the ambition lives.
The quick answer
Choose Arc if…
- You need Windows as well as macOS, or the iOS companion (Arc Search)
- You rely on Chrome extensions — Arc runs the Chrome Web Store
- You want account-based sync across machines
- You love Boosts (custom CSS/JS per site) and Arc’s profile-per-Space model
Choose Sill if…
- You want the sidebar-and-workspaces idea without an account requirement
- You want workspaces that actually free memory — Sill hibernates the whole room, Arc archives (closes) old tabs instead
- Privacy matters to you as architecture: Sill makes zero network calls of its own
- You want glanceable favorites — unread mail counts and meeting nudges, read locally
- You want a browser that is actively being built
Arc vs Sill: core features
| Feature | Sill | Arc |
|---|---|---|
| Engine | WebKit (native macOS) | Chromium |
| Platforms | macOS 14+ (Apple Silicon & Intel) | macOS, Windows; Arc Search on iOS |
| Price | Free (early access) | Free |
| Account required | No | Yes — sign-in required |
| Open source | Source on GitHub | No |
| Workspaces | Yes — hibernating workspaces | Spaces (with per-Space profiles) |
| Memory model | Whole workspaces hibernate and release their memory; favorites stay loaded | Auto-archives idle tabs (closes them after a set period); Spaces stay loaded |
| Ad & tracker blocking | Built in — ad networks blocked natively; videos never autoplay | Via Chrome Web Store extensions |
| AI features | None — routine detection is deterministic, local, and off by default | Arc Max (summaries, tidy titles) — optional, cloud |
| Browser's own network calls | Zero of its own — no telemetry, no analytics, no account | Account sign-in plus standard product analytics |
| Developer tools | API client, MCP explorer, Web Inspector, JSON tree viewer | Chromium DevTools; Boosts for per-site CSS/JS |
| Sync & mobile | None — single Mac, fully local | Account sync; Arc Search on iOS |
| Extensions | No extension store (blocking & dev tools are built in) | Yes — Chrome Web Store |
Accurate to the best of our knowledge as of 13 July 2026; Arc's details come from its public documentation.
Where Arc shines
- Design that changed the category. Spaces, Little Arc, the command bar and Boosts remain some of the best interaction design any browser has shipped. Much of what newer browsers (Sill included) do with sidebars and workspaces, Arc did first.
- The Chromium ecosystem. Chrome extensions, Chrome-grade site compatibility, and cross-platform reach including Windows.
- Multi-machine life. Sign in once and your Spaces follow you — something Sill deliberately does not do, because nothing in Sill leaves your Mac.
See it for yourself: visit Arc’s official site ↗ (opens in a new tab).
Where Sill shines
- Workspaces that release memory. Arc tidies by archiving — old tabs get closed. Sill hibernates: switch away and the whole workspace releases its memory, then wakes exactly where you left it, scroll position included.
- No account, no analytics, no calls home. Arc requires sign-in and collects standard product analytics. Sill makes zero network calls of its own — the only traffic is the sites you visit.
- Heads-up favorites. Unread mail on the Gmail icon and a quiet nudge before meetings, read locally from your own signed-in pages — nothing Arc offers, and nothing sent anywhere.
- Built-in developer tools. A full API client, an MCP explorer, and the Web Inspector on every page — no extensions needed.
The privacy picture
Arc's privacy posture is conventional and documented: an account is required, product analytics are collected, and its privacy policy governs the rest. Sill's is architectural: no account exists to create, no telemetry exists to disable, and routine observation (off by default) is metadata-only, runs locally, and never touches banking, health or government sites. If you'd rather verify than trust, Sill's zero-calls claim is watchable in Little Snitch.
Verdict
Frequently asked questions
Is Arc still being developed?
Per The Browser Company's announcements, new feature development on Arc stopped in 2025 while the team focuses on Dia; Arc continues to receive security and maintenance updates. Atlassian announced an agreement to acquire The Browser Company in late 2025.
Are Arc Spaces and Sill workspaces the same thing?
Similar idea, different mechanics. Both group tabs by context. Arc keeps Spaces loaded and tidies by auto-archiving (closing) idle tabs. Sill hibernates the whole workspace when you switch away — memory is released entirely, and the workspace wakes with scroll position intact.
Does Sill require an account like Arc does?
No. Sill has no account, no sign-in and no sync service. Download it and go — and because there is no account, nothing about your browsing can leave your Mac.
Can Sill run Chrome extensions?
No — Sill is a native WebKit browser, not Chromium, so there's no Chrome Web Store. Ad blocking and developer tools (API client, MCP explorer, Web Inspector) are built in instead.
Try it yourself:Sill is free early access for macOS 14+ — no account, nothing leaves your Mac.
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