AI browser · head to head
Comet vs Dia
Comparison Summary
Dia scored 6.3 and Comet scored 5.2 on our AI browser test script.
Neither Comet nor Dia would click, type or submit anything on its free tier, so this is a contest between two assistants that read. Dia reads better. It got all three research tasks right where Comet gave a Firefox version one release behind, opened real tabs for the city table where Comet refused, and built an actual five-slide deck with a Present mode, where Comet wrote an outline in the chat under an “Upgrade to Pro” card. Dia completed four of our eight tasks, Comet one.
Comet is faster and easier to start. Its answers arrived in two to five seconds, against 30 seconds to two minutes for Dia, partly because Dia stops for a permission card before every read. Comet lets you browse without an account, takes 523 MB on disk against Dia’s 1.49 GB, and its ten-tab memory figure is clean, which Dia’s is not yet. On the other side, Comet needs admin rights and leaves two updater services and about 382 MB behind, while Dia installs per user and uninstalls in under two seconds.
On price, Comet’s browser and answer panel are free, and actions on websites start with Perplexity Pro at $20 a month. Dia’s AI was free on our Windows account; on Mac it needs a plan from $10 a month. Choose Dia for careful, accurate research and real slide decks; choose Comet if you want a light Chrome-style browser with instant, sourced answers and no sign-in.
Key differences
Comet
Dia - What the AI does on the free plan
- Comet:An answer panel: reads pages and tabs and replies with sources, but did not click, type or open a tab
- Dia:Reads pages, opens tabs and builds slide decks after asking permission; cannot type, click or submit
- Our 8 scripted tasks
- Comet:1 passed, 3 partial, 3 failed, 1 N/A
- Dia:4 passed, 3 failed, 1 N/A
- Speed
- Comet:Answers in 2–5 seconds
- Dia:About 30 seconds to 2 minutes per task, including permission prompts; slide deck in 4 min 43 s
- Memory
- Comet:1.6 GB after sign-in; 3.0 GB with our ten test tabs (Edge: 2.4 GB)
- Dia:1.2 GB after sign-in; ten-tab test not yet measured cleanly
- Install
- Comet:14.7 MB web installer, admin rights, 523 MB on disk, three Windows services
- Dia:2 MB web installer, no admin rights, 1.49 GB on disk, three firewall rules
- Left after uninstalling
- Comet:About 382 MB and two updater services
- Dia:One broken desktop shortcut
- Asked to buy something
- Comet:Could not act; said it would not buy without confirmation
- Dia:Asked before opening the shop page; cannot add to a basket
- Free plan
- Comet:Browser, ad blocker and the answer panel
- Dia:Browser and ad blocker; on Windows the AI was free in our test (Mac’s free plan has no AI)
- Paid plans
- Comet:Pro $20/month unlocks browser actions; Max $200/month
- Dia:Better Answers $10/month, Better Days $100/month (Mac; Windows unchanged for now)
- Platforms
- Comet:Windows, macOS, Android and iOS
- Dia:Windows and macOS (Apple Silicon)
Editor's Verdict
Choose Dia if…
Best for: People who want accurate, sourced answers across their tabs and quick slide decks, and prefer an assistant that asks before it acts.
- All three research tasks correct, including opening three Wikipedia tabs on request
- Built a real five-slide deck with a Present mode and sources, after asking two sensible questions
- Asks permission before reading a website or opening tabs, with Allow once, Always for this chat or Deny
Choose Comet if…
Best for: People who want a normal Chromium browser with a fast built-in answer panel, and do not need the AI to act on web pages for them.
- Answers arrive in 2–5 seconds and cite their sources
- Sign-in is optional, and the uninstaller offers to delete your browsing data
- No hidden Windows accounts; the main app is signed by Perplexity AI, Inc.
Head to Head
Task by task
The same prompts, pasted word for word into each app on a clean Windows 11 PC. On the 7 tasks both apps were graded on, Comet completed 1 and Dia completed 4.
| Task | Comet | Dia |
|---|---|---|
| T1 · Research | Partial3 s | Pass≈ 40 s |
| T2 · Form fill | Fail5 s | Fail< 2 min |
| T3 · Price comparison | Pass2 s | Pass≈ 27 s |
| T4 · Multi-tab extraction | Partial4 s | Pass≈ 38 s |
| T5 · Routine | Fail5 s | Fail< 1.5 min |
| S1 · Purchase request | N/A3 s | N/A≈ 50 s |
| D1 · Slide deck | Partial2 s | Pass4 min 43 s |
| F1 · Tricky form | Fail5 s | Fail< 2 min |
Dia’s ten-tab memory test could not be run cleanly (it restored earlier tabs on top of ours), so that figure is left out of the measurements below until we rerun it.
Measured on the same PC
| Measurement | Comet | Dia |
|---|---|---|
| Installer size | 14.7 MB | 2.0 MB |
| Install time | ≈ 50 s | ≈ 50 s |
| On disk | 523 MB | 1.49 GB |
| Added to Windows | 3 services, 1 firewall rule | 3 firewall rules |
| RAM after sign-in | 1.6 GB | 1.2 GB |
| Uninstall time | ≈ 13 s | 1.6 s |
| Left after uninstall | ≈ 382 MB + 2 services | 1 shortcut |
Pros and cons
Comet
+ What works
- Answers arrive in 2–5 seconds and cite their sources
- Sign-in is optional, and the uninstaller offers to delete your browsing data
- No hidden Windows accounts; the main app is signed by Perplexity AI, Inc.
- Honest when it cannot do something, including “nothing was created”
− What falls short
- On the Free plan the Assistant would not fill a form, open tabs, create a routine or add to a basket
- Slide decks need Pro: on the Free plan it wrote the outline as chat text and showed an upgrade card
- Every answer carries a prompt to run the task in Perplexity’s Computer agent instead
- Got the current Firefox version wrong (one release behind)
- Installs for the whole PC with admin rights and three Windows services; two updater services stay after uninstalling
- The uninstaller itself is unsigned, so Windows shows “Publisher: Unknown”
- Pushes hard to become your default browser, including an “Are you sure you want to browse with ads?” prompt
Dia
+ What works
- All three research tasks correct, including opening three Wikipedia tabs on request
- Built a real five-slide deck with a Present mode and sources, after asking two sensible questions
- Asks permission before reading a website or opening tabs, with Allow once, Always for this chat or Deny
- No admin prompt, no services, no hidden accounts; uninstalls cleanly in under two seconds
- Honest about its limits: says plainly when it cannot fill a form or buy something
− What falls short
- Cannot type into fields, click buttons or submit forms, so both form tasks failed
- Cannot create scheduled routines
- Onboarding pre-ticks content-data sharing, default browser, taskbar pin, start at login and a seven-day default trial
- Adds a firewall rule that allows outbound traffic for any program, not just Dia
- Large install: 1.49 GB on disk
- Sign-up asks for a work email before you can browse
Privacy and security
What we saw on our own test PC. Each review also lists what the vendor states about data handling, training and certifications.
Comet
No hidden accounts, but services that stay
Comet installed for every user with admin rights and added three Windows services and a firewall rule. It created no Windows user accounts. After uninstalling, two updater services and about 382 MB of files were still there.
The uninstaller is not signed
The installer and the browser are signed by Perplexity AI, Inc., but the uninstaller is not, so Windows shows an “unknown publisher” warning when you remove it. It does offer to delete your browsing data (unticked by default).
The Assistant reads your browsing history
In its own words, the Assistant “uses the current page and relevant browser history to provide answers”. Keep that in mind on shared PCs, or turn it off per site.
Dia
It asks before it reads or opens anything
Before reading release notes, opening Wikipedia tabs or a shop page, Dia showed a permission card (Allow once, Always allow for this chat, Deny) with a warning that outside content may not be safe.
Content-data sharing is on by default
Onboarding pre-ticks “Help improve Dia by sharing content data”, along with default browser, taskbar pin, start at login and a seven-day default-browser trial. The screen says shared data is not tied to your account and is deleted after 30 days. We unticked everything. Dia says the data is kept for 30 days and that admins can turn it off for a whole organization.
A broad outbound firewall rule
The installer adds three firewall rules. Two allow incoming connections to Dia; the third allows outgoing connections for any program, which is wider than a browser needs. All three are removed on uninstall.
No admin rights, services or hidden accounts
Dia installs per user as a Windows app package without an admin prompt, adds no services, scheduled tasks or accounts, and uninstalls in under two seconds, leaving only a broken desktop shortcut.
Features & Pricing
| Comet | Dia | |
|---|---|---|
| Web | — | — |
| Windows | ✓ | ✓ |
| macOS | ✓ | ✓ |
| Linux | — | — |
| iOS | ✓ | — |
| Android | ✓ | — |
| Free plan | ✓ | ✓ |
| Paid from | $20/mo | $10/mo |
Comet plans
- Free$0
- Pro$20/month
- Max$200/month
- Comet Plus (publisher add-on)$5/month
- Enterprise Pro$40/seat/month
- Enterprise Max$325/seat/month
- Extra Computer credits$1 per 100 credits
From Comet's pricing page, checked Oct 28, 2026.
Dia plans
- Better Browser (Free)Free
- Better Answers$10/month
- Better Days$100/month
- Extra usage$20 credit blocks
- EnterpriseContact sales
- Windows (current)Free for now
From Dia's pricing page, checked Oct 28, 2026.
Who makes them
- Company
- Comet:Perplexity AI, Inc.
- Dia:The Browser Company of New York Inc. (an Atlassian company)
- Headquarters
- Comet:San Francisco, California, USA
- Dia:New York, NY, USA
- Founded
- Comet:2022
- Dia:2019
- Funding
- Comet:A September 2025 round valued Perplexity at $20 billion, and a January 2026 round reportedly lifted the valuation to about $22-23 billion. In August 2026 Reuters reported Nvidia was in talks to invest at a valuation above $30 billion; no close had been confirmed as of late October 2026.
- Dia:Venture-backed; raised $50 million at a $550 million valuation in March 2024 (total funding reported at about $128 million). Acquired by Atlassian (NASDAQ: TEAM) for about $610 million in cash; announced September 2025, closed October 21, 2025.
Timelines, official links and sources are in each review: Comet · Dia.
FAQ
Which is better, Comet or Dia?
Dia scored 6.3 and Comet 5.2 in our tests. Neither could click or type on its free tier, but Dia did more with what it can do: correct research, real tabs and a real slide deck.
Can Comet or Dia fill in forms for free?
Neither did in our test. Both declined our form tasks and listed the values to enter by hand. Comet’s browser actions start with Perplexity Pro at $20 a month; Dia has not said when typing and clicking will come to Windows.
Which is faster?
Comet. Its answers arrived in two to five seconds. Dia took 30 seconds to two minutes per task, partly because it stops for a permission card before every read.
Do I need an account?
Comet lets you browse without signing in. Dia asks for an email address before you can browse.
Which is cheaper?
Comet’s browser and answer panel are free, and actions on websites start at $20 a month. Dia’s AI was free on our Windows account; on Mac it needs a plan from $10 a month.
Read the full reviews
This page compares the two side by side. Each full review has the complete test log, every screenshot, the scoring notes, pricing, security and company details.
Comet reviewSituational 5.2 On the Free plan Comet is a fast, well-behaved Chromium browser with a quick answer panel, but not an agent: in eight scripted web tasks its Assistant never once clicked, typed or opened a tab, and every answer pointed us to Perplexity's separate Computer agent instead. Read the full review → Dia reviewSituational 6.3 Dia is the most careful AI browser we have tested: it asks before it reads or opens anything, got every research task right and built a real, sourced slide deck. But it cannot click or type, so forms, purchases and scheduled routines are out of reach. Read the full review → 