Every major browser maker is racing to put an AI agent inside the address bar, and the lineup has shuffled fast: OpenAI's ChatGPT Atlas shipped for Mac in October 2025 and was already discontinued by August 2026, folded back into the ChatGPT desktop app and Chrome extension. The four AI browsers that are still standing on Mac and actively shipping updates are Comet from Perplexity, Dia from The Browser Company, Opera Neon, and Brave with its built-in Leo assistant.

They take four different bets on what "AI in the browser" should mean: an agent that acts across tabs and apps for you (Comet, Neon), an assistant that helps you write and plan around your open tabs (Dia), or an AI layer bolted onto an already-established privacy browser (Brave). This guide compares all four on pricing, agentic capability, extensions, platform support, and privacy, so you can pick the one that fits how you actually browse.

Quick Verdict

Choose Comet if you want the most capable free agentic browser: it can research, shop, and complete multi-step tasks across tabs, and the core AI features cost nothing.

Choose Dia if you live in Slack, Notion, GitHub, and your calendar, and want an AI that turns that scattered context into morning briefs, meeting prep, and slide decks, not an agent that clicks around the web for you.

Choose Opera Neon if you want the most autonomous "do it for me" agent, with dedicated Chat, Do, and Make modes and access to top-tier models, and you're fine paying a subscription for it.

Choose Brave if you already want a fast, privacy-first, Chromium-based daily driver with full Chrome extension support, and you'd rather have AI as a free, optional sidebar than the reason you switch browsers.

Feature Comparison

Comet

Comet launched in July 2025 gated behind Perplexity's $200/month Max plan and dropped that paywall on October 2, 2025, making the core browser and its agent free worldwide. That makes it the most accessible agentic browser here: without paying anything, Comet can summarize pages, run agentic search, block ads, use voice mode, and take actions across tabs, like comparing prices while you shop or pulling data together from several open sites, using a limited monthly allotment of agent credits.

Comet Plus, a $5/month add-on (included free for Perplexity Pro and Max subscribers), layers in licensed publisher content inside its AI answers. Because Comet is built on Perplexity's own search and answer engine, it leans more toward research and information tasks than Opera Neon's broader "build me a website" ambitions, but it's the only browser in this group with genuinely capable agentic actions on a free plan.

Choose Comet if you want an AI browser that can actually act on your behalf, not just chat about your tabs, without paying a subscription to get there.

Dia

Dia is the successor to Arc from The Browser Company, and it takes the most conservative approach to AI of the four: instead of an agent that clicks around the web for you, Dia's sidebar assistant answers questions about your open tabs, drafts writing from that context, and increasingly pulls in your actual work tools. Its newer features, Morning Brief, Synthesis Reports that aggregate Slack, Notion, and Calendar into one summary, and auto-generated Decks, position Dia as a browser for people whose work lives across several SaaS tools rather than the open web.

The tradeoff is platform support: Dia currently runs only on Apple Silicon Macs with macOS 14+, with no Intel Mac, Windows, iOS, or Android build (a Windows version is in development). The free tier covers light AI use; Pro at $20/month, with a 14-day trial, unlocks chatting across all open tabs simultaneously and extended cross-session Memory.

Choose Dia if your work is scattered across Slack, Notion, GitHub, and meetings, and you want AI that synthesizes that context rather than one that browses the open web for you.

Opera Neon

Opera Neon is the most ambitious agent of the group. Instead of one assistant, it ships three: Chat for conversation, Do for reading a page, carrying context, and completing tasks, and Make for generating code, documents, websites, and videos from a prompt. A dedicated deep-research agent (ODRA) handles sustained, multi-step investigation, and Neon connects to external tools through MCP.

Opera Neon originally shipped in September 2025 as a $19.90/month subscription-only browser; by August 2026 Opera made the base browser free to download for Mac and Windows, keeping the agentic features (top-tier models like Gemini 3 Pro and GPT-5.1) behind the subscription. That makes it the most "hands-off" browser here, at the cost of being the only one where the headline AI features aren't usable for free.

Choose Opera Neon if you want a browser that can genuinely build things (a report, a webpage, a script) rather than just answer questions, and you're willing to pay for that capability.

Brave

Brave isn't a new AI-first browser; it's an established, privacy-focused Chromium browser (with the strongest default ad and tracker blocking of the four) that added an AI assistant, Leo, as one feature among many. Leo summarizes the current page, answers questions about it, translates, analyzes PDFs and Google Docs, and drafts text or code, all without requiring an account, and without retaining your chats or using them for training.

Where Brave differs most from the other three: it has no autonomous agent that acts across tabs or completes multi-step tasks, and it's the only browser here with full cross-platform support, including Linux. The free tier covers Brave's own Ocelot model plus limited Claude access; Leo Premium at $14.99/month raises usage limits and unlocks higher-tier Claude models. For most people, Brave is the browser you'd switch to for speed, privacy, and extension compatibility, with Leo as a free bonus rather than the reason to install it.

Choose Brave if you want a genuinely private, fast, extension-compatible daily browser and see AI as a nice-to-have, not the main event.

Which AI Browser Should You Use?

Use Comet if you want the most capable free agent for research and shopping tasks across tabs, and you're already inside Perplexity's ecosystem or open to it.

Use Dia if your day is spent context-switching between Slack, Notion, GitHub, and meetings, and you're on an Apple Silicon Mac.

Use Opera Neon if you want AI that builds and completes things autonomously, and a $19.90/month subscription is worth it for that.

Use Brave if privacy, speed, and full extension support matter more to you than agentic AI, and you want a free assistant on top rather than a subscription.

Final Verdict

Comet is the best all-around pick for most Mac users because it offers genuine agentic capability, tab summarization, and agentic search for free, with no subscription required to get real value.

Dia is the best choice for tab-heavy knowledge workers who want AI synthesis of their scattered work tools, provided they're on a recent Apple Silicon Mac.

Opera Neon is the best choice for people who want maximum autonomy from their browser's AI, at the cost of paying for it.

Brave is the best choice if you'd rather not change your browsing habits at all, keeping a fast, private, extension-friendly browser with AI as an optional layer.

My practical recommendation: start with Comet since the agentic features are free and genuinely useful, and keep Brave as your daily driver if privacy and extension compatibility matter more to you than an AI agent. Reach for Dia or Opera Neon only if their specific approach (tab-context synthesis, or full task automation) solves a problem the others don't.

Note: Features and prices are current as of September 2026. AI browsers are changing quickly (Opera Neon dropped its paywall on the base browser in August 2026, and OpenAI shut down ChatGPT Atlas the same month), so verify current pricing and platform support on each developer's official site before subscribing.