Sigma Browser
A private AI browser. Impressively light. Packed with features.
About Sigma Browser
Sigma is a desktop and mobile browser with AI built into it rather than bolted on as an extension, and its distinguishing bet is privacy. The AI agent can navigate sites, click buttons, fill fields, submit forms and gather data the way a person would, so booking a ticket or clearing an inbox becomes a described goal rather than a sequence of clicks. Deep Research queues sources, clusters what it finds and returns structured output. Chat with Page turns whatever is on screen into something you can question directly. None of that is unusual on its own in 2026; what is unusual is Eclipse, a local LLM running inside the browser, which processes prompts on your device with nothing sent to a server.
That local path is the reason to look at Sigma over the other agentic browsers. Anything you run through Eclipse - summarising, writing, questioning a page - stays on the machine, which changes what is safe to point it at. The rest of the privacy story is conventional but present: end-to-end encryption on user data and AI conversations, encrypted private profiles unlocked by a 12-word phrase for separating work from personal browsing, real-time phishing detection, a built-in ad blocker, GDPR and CCPA compliance, and a stated policy of not retaining credentials or task data after an agent run finishes. The site says the browser code is public for review. Standard browser extensions work, and there is Web3 and wallet support for people who need it. It runs on macOS, Windows and iOS today, with Android on a waitlist (an APK is available for manual install) and Linux listed as coming.
Download and install it as you would any browser: a DMG on macOS, an EXE on Windows, the App Store on iPhone. It behaves like a normal browser from there, extensions included, so nothing about ordinary browsing has to change.
For agent work, describe the goal rather than the steps. The agent interacts with sites the way a real user does, clicking through, filling in fields, submitting forms and collecting what it finds along the way, then reports back. The examples the site gives are booking tickets, managing an inbox, paying bills, posting to social media and updating spreadsheets.
For research, Deep Research takes a question, works across multiple sources, and clusters the results into structured insight rather than a list of links. Chat with Page is the lighter version of the same idea, scoped to the tab in front of you, and Quick Translate handles a highlighted sentence in place.
For anything you would rather not send anywhere, switch to Eclipse. It answers, summarises and writes locally, on the device, with no cloud round trip. That path is slower on a weak machine and stronger on privacy, which is exactly the trade you would want to be able to make deliberately.
- •AI Agent - Operates websites end to end on your behalf: navigating, clicking, filling forms and gathering data, driven by a goal you describe rather than steps you perform. Credentials and task data are not retained after execution.
- •Eclipse local LLM - A model running inside the browser that processes everything on-device, with no prompts leaving the machine. The feature that most directly separates Sigma from cloud-only agentic browsers.
- •Deep Research - Queues sources, clusters findings and produces structured output rather than a link list, for questions that span more than one page.
- •Chat with Page and Quick Translate - Question or summarise the current page without leaving it, and translate any highlighted sentence in place.
- •Encrypted private profiles - Separate spaces for work, personal and per-account browsing, encrypted and unlocked by a 12-word phrase.
- •Built-in ad blocker and phishing detection - Ads filtered at the browser rather than by an extension, and suspicious sites flagged in real time before you land on them.
- •Extensions and Web3 support - Standard browser extensions install and run as normal, with blockchain and wallet connectivity for people who need it.
People who want an agentic browser but will not send their browsing to a model provider are the specific audience, and Eclipse is the whole answer to that. If the objection to Comet or Dia is that the useful part requires handing pages to a cloud service, a local model inside the browser is the direct response to it.
Researchers and analysts get Deep Research and Chat with Page, which together cover the read-many-sources-and-synthesise work that a normal browser makes tedious. Founders and operators get the agent for the repetitive account admin that fills a week: forms, bookings, inbox triage, spreadsheet updates.
Developers evaluating it should note that the site claims the browser code is public without linking a repository from the homepage, so verify that yourself if code review is part of your decision. Anyone on Linux is waiting, and Android is a waitlist with a manual APK for the impatient. The free tier is genuinely usable for chat and page work, with limits on the agent, image generation and Deep Research that Plus at $10 a month raises and Pro at $75 removes.
