If you want the most capable AI browser, pick Perplexity Comet — it packs the full Perplexity research engine, citation-backed answers, a genuinely free agent mode, and it runs everywhere. If you want a fast, distraction-free browser with a smart sidebar and reusable Skills, pick Dia — just know it's macOS-only and its AI is more assistant than autonomous agent. Comet is the power tool; Dia is the daily driver.
Quick verdict
Pick Comet for research, cross-tab reasoning, and agentic tasks — booking, form-filling, multi-step lookups — for free, on any platform. Pick Dia if you're on a Mac and want a lightweight Chrome replacement with an AI chat that reads your tabs and Skills you can trigger by name. They're aimed at different needs more than they compete head-on.
Side by side
| Perplexity Comet | Dia | |
|---|---|---|
| Maker | Perplexity | The Browser Company (Arc's team) |
| Best for | Research & agentic tasks | Fast, simple everyday browsing |
| AI engine | Full Perplexity + agent mode | Sidebar chat (OpenAI & others) |
| Standout feature | Citation-backed research | Skills + strong tab management |
| Platforms | Mac, Windows, iOS, Android | macOS 14+ (Apple silicon) only |
| Price | Free (Plus $5/mo) | Free; Pro $20/mo |
The case for Comet
Comet replaces Google search with Perplexity's AI engine, so every query returns a synthesized, cited answer instead of a page of blue links. It maintains context across your open tabs and, since Perplexity dropped the paywall in March 2026, its full agent mode is free on Mac, Windows, iOS, and Android. That's a lot of capability at no cost.
For anyone who researches, compares, or runs multi-step web tasks all day, Comet is the stronger tool. Our Comet review covers the workflow in depth, and Comet pricing breaks down the optional paid add-ons.
The case for Dia
Dia comes from The Browser Company, the team behind Arc, and it's their answer to "Arc was too complicated." It looks like Chrome with a built-in AI sidebar that chats with you, answers questions about your open tabs, and generates text from page content. Its headline features are Skills (reusable AI routines you trigger by name, with a marketplace), Memory, and Tab Groups for Meetings.
Day to day, Dia is fast, stable, and quiet — many users report months without a crash, and there's no learning curve if you can use Chrome. It also has noticeably better tab management than Comet. The full breakdown is in our Dia browser review.
Agents and research
This is the clearest gap. Comet has the full power of Perplexity, including a free agent mode that can actually take actions across the web and reason over multiple tabs and sources. Dia's AI is primarily a sidebar assistant — a well-built wrapper around OpenAI and other models — that's great for asking about the current page but isn't a true autonomous agent.
So if your reason for switching to an AI browser is "do work for me," Comet delivers more. If it's "help me understand what's on this page and speed up repetitive prompts," Dia's Skills are elegant and fast.
Platforms and privacy
Comet wins on reach — it's on Mac, Windows, iOS, and Android, so your AI browser follows you across devices. Dia runs only on macOS 14+ with Apple silicon, which rules out Windows users and older Macs entirely.
On privacy, both warrant caution. Agentic browsers that read pages and take actions have a real prompt-injection attack surface — security researchers have shown Comet following hidden instructions buried in web pages. Dia's lighter, sidebar-first approach is less exposed simply because it does less autonomously, but neither is a privacy-first browser. If that's your priority, a Brave-with-Leo setup fits better; see our Comet alternatives.
Which should you pick?
Choose Comet if you want the most powerful, cross-platform AI browser with real research and agent capabilities — and it's free, which makes it an easy first install. Choose Dia if you're on a modern Mac and want a fast, simple browser with a helpful AI sidebar and reusable Skills rather than a full agent.
Want the whole field? See our best AI browsers ranking, and if you're weighing Comet against OpenAI's entry, read Comet vs ChatGPT Atlas.
Frequently Asked Questions
Is Dia or Comet the better AI browser in 2026?
Comet is more powerful — full Perplexity engine, citation-backed research, free agent mode, and cross-platform support. Dia is faster and simpler with great tab handling and Skills, but it's macOS-only and more sidebar assistant than agent.
Is Dia free?
Dia's base browser is free with limited AI use; Dia Pro is $20/month and removes AI limits. Comet's full browser, including agent mode, is free, with an optional $5/month Comet Plus add-on.
Does Dia work on Windows?
No. Dia runs only on macOS 14 or later with Apple silicon. Comet is cross-platform across Mac, Windows, iOS, and Android.
Which is better for research?
Comet, clearly. It replaces search with Perplexity's cited answers and reasons across tabs. Dia can summarize the current page and your open tabs but doesn't match Comet's depth for multi-source research.
What are Dia's Skills?
Skills are reusable AI routines you save and trigger by name — essentially pre-set prompts for common tasks. There's a marketplace where you can grab and modify others' Skills, which is Dia's most distinctive feature.
Are AI browsers safe to use?
Use them carefully. Agentic browsers can be tricked by hidden instructions embedded in web pages — a documented risk with Comet. Avoid running agent mode on sensitive accounts, and treat any AI browser as more exposed than a traditional one.
Can I use both?
Yes, and some people do — Comet for heavy research and agent tasks, Dia as a lighter everyday Mac browser. Neither locks you in, so trying both is low-cost since the core of each is free.