Perplexity Comet vs Dia: Our Verdict
Two AI browsers built on Chromium, two very different bets. One turned a $200 tier free and put an agent on your desktop. The other rebuilt the browsing surface for a quieter kind of knowledge work, and asks $20 a month to unlock it.
Comet is the AI browser we recommend for most knowledge workers. It's free across Mac, Windows, iOS, and Android, its agent will actually drive multi-site tasks, and its research surface is Perplexity's, cited and cross-tab-aware. Dia is the better daily read-and-write companion, but it's Mac-only, its agentic ambitions are thinner, and its $20 Pro tier costs the same as the AI features Comet gives away.
Both products answer the same question, what does a browser do when a language model sits inside it, with nearly opposite strategies. Comet is a Chromium browser wrapped around Perplexity's answer engine, with an agent that can read pages, span tabs, and act on the user's behalf. Dia is a Chromium browser from the Arc team (now an Atlassian subsidiary) that strips the interface back and promotes a sidebar assistant and reusable prompt "Skills" to first-class citizens.
We tested both on the same knowledge work: reading and summarizing long articles, chatting across a handful of open tabs, running a multi-step research task, and drafting inside the browser. Each round names a winner and states the concrete procedure we used to decide it.
Comet is a free download on Mac, Windows, iOS, and Android, with no waitlist. Dia is macOS-only and requires Apple Silicon on macOS 14 or later; the Windows build is still in development and gated behind a signup list. For any team that isn't uniformly on modern Macs, the reach gap decides the match on its own.
How we tested itWe installed each browser on every platform its maker ships to and recorded which operating systems, chip architectures, and mobile targets were supported without a waitlist as of July 2026.
Comet itself is free, with the headline AI features intact on the free tier; Comet Plus is $5/month for premium publisher content, and Perplexity Pro at $20/month unlocks the deeper AI features and bundles Comet Plus. Dia is free with undisclosed AI usage caps, and Dia Pro is $20/month for uncapped chat and Skills. At the entry tier, Comet is free where Dia is limited; at $20, the two draw even on AI access, but Comet also brings a real agent.
How we tested itWe priced a month of normal individual use on each product's public tiers, then re-priced a heavier week that leaned on the AI features to see what a working knowledge worker actually pays.
Comet's assistant will genuinely drive a browser: it filled forms, moved across sites, and returned a structured result on the pricing and specs tasks, and cleared most of the inbox job before we intervened. Reliability is uneven, community testing has fairly described agentic tasks as "70% magic, 30% comedy", but the agent exists and works often enough to matter. Dia's assistant is a strong reader and writer, but it doesn't drive the browser through multi-step tasks in the same way.
How we tested itWe assigned each browser the same three multi-step web tasks, comparing three project management tools' pricing pages into a table, cleaning out a promo-heavy inbox, and pulling five product specs from separate retailer sites into one document, and recorded how many steps each completed before needing human help.
Comet's research surface is Perplexity's engine built into the browser rather than bolted on, with citations on every answer and cross-tab awareness through @tab references. Dia's assistant answers questions about open tabs well but is less transparent about which model is running and less consistent about citing sources for open-web claims.
How we tested itWe ran the same five research prompts in each browser (a legal question, a comparative shopping question, an academic topic, a current-events question, and a technical how-to) and scored answers for source coverage, inline citations, and the ability to pull context from open tabs.
Dia is the more considered daily companion. The chat is quicker to reach, the writing help in text boxes is better tuned, and Skills, reusable prompt shortcuts, make repeated tasks (rewrite in our house voice, extract action items, summarize a thread) faster than typing the same instruction into Comet's sidebar each time. For readers and writers who aren't trying to delegate the browser, Dia is the more polished surface.
How we tested itWe spent a working day in each browser on ordinary tasks, reading long articles, drafting email replies inside webmail, chatting with a stack of research tabs, and writing a short document from notes, and rated interface friction, output quality, and how often the AI got in the way.
Dia's public position is that user data is stored locally on the device and encrypted, that data sent to an external server for processing is deleted within milliseconds, and that the goal is to move processing on-device over time. Comet's enterprise tier ships MDM deployment, 500+ Chromium policies, per-session audit logs, and a CrowdStrike Falcon integration for phishing and data-exfiltration controls, which is the stronger story for regulated organizations, but at the individual level, Dia's default posture asks the user to trust the model with less.
How we tested itWe read each product's published privacy documentation, checked what data is stored locally versus sent to a server, and looked at the enterprise controls each maker offers for organizations.
Where the verdict turned
Comet and Dia are the two AI browsers worth weighing in mid-2026, and they aren’t interchangeable. Comet took the rounds that most affect who can actually use the product and what it can do for them: platform reach, pricing at the door, agentic execution, and research. The Perplexity Comet browser is genuinely free to download and use, on Mac, Windows, iOS, and Android, with no account required for basic browsing. Dia, by contrast, is currently available on Apple Silicon Macs running macOS 14 or later, with Windows on a signup-only waitlist and no Linux or Intel Mac support as of mid-2026 . That single fact settles the recommendation for any reader on Windows, an Intel Mac, or a mixed-device team.
Dia took the two rounds about how the browser feels once you’re inside it. It’s faster to reach the assistant, its writing help is better calibrated, and its Skills, reusable prompt shortcuts, turn repeated instructions into a single keystroke. If your day is reading, writing, and thinking, Dia is the more considered surface. It just isn’t the surface most people can install.
What each product actually is
Comet is Chromium underneath, with a persistent AI sidebar and cross-tab awareness at the front. Where Chrome or Safari passively display content, Comet actively reads pages, synthesizes across multiple tabs simultaneously, and can execute tasks on the user’s behalf, filling forms, drafting emails, booking travel, unsubscribing from mailing lists, without you doing each step manually. It launched in July 2025 as a paid product bundled into Perplexity’s $200/month Max tier, and Perplexity announced Comet was available worldwide and free to users on October 2, 2025, four months after that Max-only debut .
Dia is also Chromium underneath, from the team that built Arc. Dia was first teased on December 2, 2024, entered private beta on June 11, 2025, and reached general availability on macOS on October 8, 2025. The design deliberately walks back Arc’s power-user surface: Dia is a Chromium-based browser with a built-in AI assistant in the sidebar, custom AI shortcuts (“Skills”), a personal-context Memory feature, and Tab Groups including auto-organized meeting tab groups. Ownership changed in the same window: The Browser Company was acquired by Atlassian for $610M, and the team continues building both browsers with more financial backing to hire more .
The pricing story is not the same at $0 and at $20
At $0, Comet is dramatically more product. The free Comet ships with the headline AI features intact: agentic search, page summarization, voice mode, shopping assistance and Deep Research from inside the browser. Dia’s free tier, by contrast, is capped: Dia’s $20-per-month Pro plan is billed as “unlimited” AI access but is subject to Terms that can curb heavy use, and is aimed at heavy users of the AI assistant . The Browser Company’s CEO said Dia would remain free for people who use its AI tool only “a few times a week” , without publicly defining the cap.
At $20, the comparison changes shape but not conclusion. Twenty dollars in the Perplexity ecosystem buys Perplexity Pro, which unlocks the deeper AI features across the browser and folds Comet Plus in for free. Twenty dollars at Dia buys uncapped chat and Skills, and nothing else. If the reader values the agent, the ability to hand a task to the browser and get a result, Comet is the better $20.
Who should install which
Install Comet if you want the widest reach, the strongest research surface, and an agent that will genuinely drive the browser through multi-step tasks. It’s the pick for researchers, analysts, and anyone whose day includes cross-tab synthesis or repetitive web work. The free tier is enough for most people, and the $20 Pro upgrade is a defensible subscription on its own terms. The reliability gaps in agent mode are real; use it as an assistant, not an autopilot.
Install Dia if you’re on an Apple Silicon Mac, you read and write more than you delegate, and you value a quieter interface. Skills are the standout feature and the reason to consider Pro; the free tier is enough to try before committing. For any reader outside that narrow profile, Windows, Intel Mac, a mixed-device team, or a workflow that leans on real agentic execution, Comet is the recommendation.