Browser comparison
Dia vs Sill: the AI browser and its deliberate opposite
Dia and Sill are both new macOS browsers, and they answer the same question in opposite ways. Dia puts a cloud AI assistant at the center of browsing; Sill's smartest feature is a deterministic engine that never leaves your Mac and is off by default. Which trade suits you is the whole comparison.
Full disclosure: this studio builds Sill. This is written as the comparison worth reading anyway — Dia's genuine strengths included, its details drawn from its own public documentation.
Dia is The Browser Company's second act (now under Atlassian's wing, per the acquisition announced in 2025): a browser built around an assistant that can see your tabs, chat about them, and draft with their context. When that's what you want, Dia isn't a browser with AI bolted on — it's the real thing, designed around the assistant from day one.
Sill is the deliberate opposite. There is no LLM anywhere in it. Its one "smart" behaviour — noticing you open Mail, then Calendar, then the news most mornings, and offering to make that a workspace — is a deterministic engine you could read line by line, runs entirely on your Mac, and ships switched off. The comparison is really a values question wearing a features hat.
The quick answer
Choose Dia if…
- You want to chat with your open tabs — summarize, compare, extract — as a first-class feature
- You draft a lot of writing and want the browser to help with the context you have open
- You like skills/automations built around an assistant
- You're comfortable with page context going to cloud models when you invoke the AI
Choose Sill if…
- You want certainty that page content never leaves your Mac — Sill makes zero network calls of its own
- You want structure for heavy browsing: hibernating workspaces, Panel view, glanceable favorites
- You want no account — Dia requires sign-in, Sill has nothing to sign into
- You build things: API client, MCP explorer and Web Inspector are built in
Dia vs Sill: core features
| Feature | Sill | Dia |
|---|---|---|
| Engine | WebKit (native macOS) | Chromium |
| Platforms | macOS 14+ (Apple Silicon & Intel) | macOS (beta) |
| Price | Free (early access) | Free (beta; pricing may evolve) |
| Account required | No | Yes — sign-in required |
| Open source | Source on GitHub | No |
| Workspaces | Yes — hibernating workspaces | No — a simple tab model, by design |
| Memory model | Whole workspaces hibernate and release their memory; favorites stay loaded | Standard Chromium tab handling |
| Ad & tracker blocking | Built in — ad networks blocked natively; videos never autoplay | Limited (beta) |
| AI features | None — routine detection is deterministic, local, and off by default | The core product — chat with your tabs, skills (cloud models) |
| Browser's own network calls | Zero of its own — no telemetry, no analytics, no account | Account, telemetry, and page context sent when you use the AI |
| Developer tools | API client, MCP explorer, Web Inspector, JSON tree viewer | Chromium DevTools |
| Sync & mobile | None — single Mac, fully local | macOS only (beta) |
| Extensions | No extension store (blocking & dev tools are built in) | Chromium-based; support limited in beta |
Accurate to the best of our knowledge as of 13 July 2026; Dia's details come from its public documentation.
Where Dia shines
- The assistant is genuinely the product. Dia's chat-with-your-tabs is fluid in a way sidebar chatbots aren't — ask about the five tabs you have open, draft an email from them, follow up. If AI-assisted browsing is the goal, this is the purpose-built option.
- Design pedigree and backing. Built by the team behind Arc, with Atlassian's resources behind it since the 2025 acquisition announcement — its roadmap is where that company's ambition now lives.
See it for yourself: visit Dia’s official site ↗ (opens in a new tab).
Where Sill shines
- A hard privacy guarantee, not a policy. Using Dia’s assistant means sending page context to cloud models — that’s how it works, and Dia is upfront about it. Sill’s guarantee is structural: zero network calls of its own, ever, verifiable with a traffic monitor.
- Organization Dia doesn’t attempt. Hibernating workspaces, Panel view for side-by-side pages, favorites that behave like the Dock — Sill is built for people who live in the browser all day.
- Glanceability without a model. Unread mail counts and meeting nudges come from reading your own signed-in pages locally — no AI needed, nothing transmitted, off until you switch it on.
- Developer tools included. Dia targets general knowledge work; Sill quietly ships an API client, MCP explorer and one-click page capture for the people who build the web as well as browse it.
The privacy picture
This is the sharpest contrast on the page. Dia's value requires sending context to cloud models when you use the assistant — reasonable, disclosed, and inherent to what it is. Sill's value requires the opposite: no account, no telemetry, no cloud, routine detection that is deterministic and local, and banking, health and government sites never observed at all. Neither is wrong; they are different answers to "what should a browser know about me, and where should that knowledge live?"
Verdict
Frequently asked questions
Does Dia send my pages to the cloud?
When you use its assistant, yes — page context goes to cloud models; that's how chat-with-your-tabs works, and The Browser Company documents this. Sill, by contrast, makes zero network calls of its own and has no AI features at all.
Does Sill have any AI features?
No. Its routine detection is a deterministic engine — not a model, no LLM anywhere — that runs locally, observes metadata only (which sites, when), and is off by default. One click deletes everything it has learned.
Is Dia free?
Dia has been free during its beta, with sign-in required. Pricing may evolve — check dia.com for current terms. Sill is free early access with no account at all.
Can I have both?
Easily — they're both macOS apps. Some people use Dia as an AI research tool and Sill as the private daily driver where mail, calendar and everyday browsing live.
Try it yourself:Sill is free early access for macOS 14+ — no account, nothing leaves your Mac.
More comparisons: Arc vs Sill · Zen vs Sill · Edge vs Sill · Chrome vs Sill · DuckDuckGo vs Sill · Brave vs Sill