By Kshetez Vinayak, founder of SupaSidebar. Last updated June 14, 2026.
TL;DR:
In the Comet vs Dia decision, Comet is the better default AI browser for most Mac users in 2026: the full assistant has been free since October 2, 2025, and it runs on Intel and Apple Silicon Macs plus Windows, Android, and iOS. Dia wins for knowledge workers living in Gmail, Slack, and Notion who want the calmer, Arc-descended interface, but it requires an Apple Silicon Mac running macOS 14 or later and keeps its best AI behind a paid plan. The full comparison tables, requirements, and pricing are below. One thing neither browser solves: a workspace system that survives switching browsers, which is where a sidebar app like SupaSidebar fits whichever one you pick.
Looking for something specific?
- Want the full Dia deep-dive? → Dia Browser Mac Review 2026
- Comparing Dia against Arc instead? → Arc Browser vs Dia Browser
- Not sold on an AI browser at all? → Best Browser for Mac in 2026
- Choosing between Comet and Dia? → You're in the right place. Keep reading.
This post covers the Comet-vs-Dia decision only: AI capabilities, browsing fundamentals, Mac hardware requirements, and pricing. It does not re-review Dia feature by feature (the Dia review does that) and it does not compare Dia to Arc (that intent lives in Arc vs Dia).
Comet vs Dia at a glance
Comet is Perplexity's AI browser: a Chromium browser with an agentic assistant that can read your open tabs, run searches, and complete multi-step tasks. Dia is The Browser Company's AI browser, built after Arc, launched publicly on macOS on October 9, 2025 and owned by Atlassian since later that month: a Chromium browser where chat with your tabs and work apps is the core interaction.
| Comet (Perplexity) | Dia (The Browser Company / Atlassian) | |
|---|---|---|
| Public launch | July 2025 (Max-only), free for everyone Oct 2, 2025 | Oct 9, 2025 on macOS |
| Engine | Chromium (Chrome extensions work) | Chromium (Chrome extensions work) |
| Core AI idea | Agentic assistant: acts across tabs, drafts, shops, automates | Chat-first browsing: talk to tabs, files, Gmail, Slack, Notion |
| Mac requirements | macOS 13+, Intel and Apple Silicon | macOS 14+, Apple Silicon only |
| Other platforms | Windows, Android, iOS | None shipped as of mid-2026 |
| Tab management | Standard Chromium tab strip, tab groups, AI tab search | Vertical tabs, sidebar, pinned tabs, Tab Groups, Focus Mode |
| Workspaces | No named workspace system as of mid-2026 | Profiles in separate windows, no Arc-style Spaces |
| Free tier | Full assistant free | Browser free, top AI features in Dia Pro |
| Paid tier | Comet Plus $5/mo (publisher content); Perplexity Pro $20/mo | Dia Pro $20/mo at the time of writing |
The rest of the post unpacks the rows that actually change the decision.
The AI: an assistant that acts vs a chat that knows your work
Comet's assistant is the agentic one. Per Perplexity's launch-week coverage, it can search the web, organize tabs, draft emails, and shop, and Max subscribers get a background assistant that runs tasks while you keep browsing. The practical wins are tab-aware questions. As one Comet user on r/perplexity_ai put it: asking the browser to "compare these three tabs and tell me where they disagree" replaced a pile of extensions for research-heavy days.
The honest caveat from the same community: the fully autonomous agent mode is still hit-or-miss. Longtime Perplexity subscribers describe it as powerful for summarizing and comparing but clumsy when it has to click through real web apps on its own. Treat the agent as a bonus, not the purchase reason.
Dia's AI is less about acting and more about context. The new tab is a chat box that can see your tabs, and Dia has spent its first year wiring that chat into work tools: Gmail and Google Calendar arrived in October 2025, Slack search in November 2025, with Notion and Confluence surfacing in chat through 2026. Dia's release notes say queries now run on GPT-5, and cross-device sync shipped in v1.26.0 in April 2026. Skills (custom AI shortcuts written in plain English) and Memory (personal-context recall) round out a genuinely coherent knowledge-work setup.
The split, stated plainly: Comet's AI does things on the open web. Dia's AI knows things about your work context. People who want an assistant that books, compares, and drafts lean Comet. People who want their browser to answer "what did Slack say about the Q3 doc" lean Dia.
Browsing fundamentals: Dia inherited Arc's interface, Comet kept Chrome's
Both browsers are Chromium under the hood, so Chrome extensions, passwords, and rendering behave as expected in each.
The interfaces diverge hard. Dia carries the Arc lineage: TechCrunch documented Dia adopting Arc's greatest hits in late 2025, and today that means a sidebar mode, vertical tabs, pinned tabs, Focus Mode, and proper Tab Groups. For anyone coming from Arc, Dia feels familiar within an hour, with two big exceptions: there are no Arc-style Spaces (Dia uses profiles in separate windows instead) and no fuzzy Cmd+T command bar (the chat box took its place).
Comet made the opposite bet. It keeps a conventional Chromium layout with the standard horizontal tab strip, and puts the assistant in a side panel. There is no Arc-style workspace system as of mid-2026. That conventional layout is exactly why switching to Comet from Chrome takes minutes, and exactly why heavy tab users eventually feel the same 40-tab chaos they had in Chrome.
One user who walked the Arc-to-Dia path wrote in an email to SupaSidebar: "I switched from Arc to Dia and I'm not quite satisfied with how it handles tab management. Then I came across your app on the Arc subreddit." That dissatisfaction shows up in both camps, because neither browser treats tab organization as its main product. The AI is the product.
Mac requirements: the Intel cutoff decides for some users
This row eliminates one browser for a chunk of Mac users, so check it first.
Comet runs on macOS 13 or later, on both Intel and Apple Silicon, per Perplexity's published system requirements. It also ships on Windows, Android, and iOS, so a mixed-device setup stays in one browser.
Dia requires macOS 14 or later AND an Apple Silicon chip (M1 or newer). Intel Macs cannot run Dia at all, and the Windows version had not shipped as of mid-2026. On an Intel MacBook, the Comet-vs-Dia question answers itself.
Pricing: Comet gave away the thing Dia charges for
Perplexity launched Comet in July 2025 exclusively for its $200-per-month Max plan, then made it free for everyone on October 2, 2025. The free version includes the assistant, page summarization, and agentic search. The optional Comet Plus add-on ($5/month, included with Perplexity's paid plans) unlocks partnered publisher content from outlets like CNN and The Washington Post, per CNBC's report.
Dia is free to download, but the deeper AI usage sits behind Dia Pro at $20 per month at the time of writing. For a student or casual user, Comet's free tier is simply more AI for zero dollars. For someone whose company already lives in Atlassian, Slack, and Google Workspace, Dia Pro can be worth the line item.
The gap neither closes: your tabs are trapped in one browser
Here is the problem that surfaces two weeks after picking either one. AI browsers are still browsers, and both assume they will be your only browser. Real Mac setups rarely work that way: Chrome holds the work SSO, Safari wins on battery, and now Comet or Dia holds the AI. Every browser switch means losing track of half your open tabs, and neither Comet (no workspace system) nor Dia (profiles, but no Spaces) gives you a project-level container that follows you across browsers.
That is the gap SupaSidebar covers. SupaSidebar is a Mac sidebar app, not a browser, and both Comet and Dia are fully supported Live Tabs browsers: their open tabs appear in one sidebar alongside tabs from Safari, Chrome, Firefox, and every other major Mac browser, and clicking a tab activates the existing tab instead of opening a duplicate. Spaces group tabs and bookmarks by project rather than by browser, so trialing Comet for a week or moving research into Dia does not scatter anything. The Command Panel brings back the fuzzy cross-browser search that Dia dropped when it replaced Arc's command bar with chat. 3,000+ Mac users have tried SupaSidebar, many of them exactly this kind of multi-browser user, and there is a free version available. The multi-browser sidebar explainer walks through the full workflow.
In practice that turns the Comet-vs-Dia decision from a migration into an experiment: install either one, keep your existing browsers, and let the sidebar hold the workspace layer all of them lack.
Conclusion: Picking what to use
For most Mac users in 2026, Comet is the safer pick: the full assistant is free, the Chrome-like interface costs nothing to learn, and it runs on Intel Macs, Apple Silicon, Windows, and mobile. Dia is the better pick for Apple Silicon users doing knowledge work inside Gmail, Slack, Notion, and Confluence who want the Arc-descended interface and will get value from Dia Pro.
By segment: Intel Mac owners take Comet, since Dia will not install. Arc refugees who miss the sidebar feel take Dia, with the caveat that Spaces did not survive the trip. Research-heavy users who mostly want summarize-and-compare take Comet's free assistant. Multi-browser users should pick either one and add a cross-browser sidebar on top, because neither browser will organize tabs that live outside it.
Next step if the multi-browser case fits: try SupaSidebar (free tier) alongside whichever AI browser wins, or read the full Dia Browser Mac Review before committing.
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 33 browsers including Safari, Chrome, Firefox, Arc, Zen, Vivaldi, Brave, Helium, Dia, and Comet. Both AI browsers in this comparison are supported, so the tab, bookmark, and workspace layer stays portable no matter how the Comet-vs-Dia decision goes, or how many times it gets revisited. If you lean Dia, the SupaSidebar vs Dia breakdown covers the tab and workspace side in more detail.
FAQ
Is Comet browser free?
Yes. Comet has been free for everyone since October 2, 2025, including the assistant, page summarization, and agentic search. The optional Comet Plus add-on costs $5 per month and adds partnered publisher content; Perplexity's paid plans include it.
Is Dia browser free?
The Dia browser itself is a free download, but the heavier AI features sit behind Dia Pro, which costs $20 per month at the time of writing. Casual use works fine on the free tier; daily AI-heavy work is where the paid plan becomes relevant.
Does Dia work on Intel Macs?
No. Dia requires an Apple Silicon Mac (M1 or newer) running macOS 14 or later. Intel Mac users who want an AI browser should look at Comet, which supports Intel Macs on macOS 13 or later.
Is Comet better than Dia?
For most Mac users, yes: Comet's full assistant is free, it runs on more hardware and more platforms, and the Chrome-like interface requires no relearning. Dia is better for Apple Silicon users doing knowledge work in Gmail, Slack, and Notion who want a calmer, Arc-influenced interface and are willing to pay for Dia Pro.
Can I use Comet and Dia at the same time?
Yes. Both are standard Mac apps and can run side by side, each with its own default-browser setting, extensions, and profiles. A cross-browser sidebar app like SupaSidebar can show live tabs from both at once, which makes running them in parallel manageable instead of chaotic.
Do Chrome extensions work in Comet and Dia?
Yes, both. Comet and Dia are Chromium-based, so Chrome Web Store extensions install in each. Note that Dia announced a Manifest V2 phase-out in early 2026, so some older extensions may only work in their Manifest V3 versions.
By Kshetez Vinayak, founder of SupaSidebar.