A new privacy-focused browser called Sigma bundles local AI models directly into the browsing experience, letting users chat with artificial intelligence without their conversations leaving their computer. Unlike Chrome or Perplexity, which rely on cloud-based AI services, Sigma ships with its own local language model called Eclipse, which runs on your hardware via llama.cpp, making it a compelling option for users concerned about data privacy.

How Does Sigma's Local AI Integration Work?

Sigma operates as a Chromium-based browser, meaning it feels familiar to anyone using Chrome or Brave. The key difference appears when you open a new tab, where three options greet you: Search, AI Chat, and Agent. The AI Chat mode runs Eclipse, Sigma's proprietary local language model, which processes your prompts entirely on your device without requiring an account, API key, or internet connection for basic functionality.

The browser also offers flexibility for users who want more powerful models. You can swap Eclipse for other local models including Gemma 4 E4B, Qwen 3.5, Nemotron 3, or GLM 4.7, all accessible through the settings. For heavier computational tasks, Sigma allows you to plug in cloud-based models from providers like Anthropic, OpenAI, or DeepSeek, creating a hybrid approach rather than a strictly local-only system.

What Privacy Features Does Sigma Include?

Sigma's privacy architecture extends beyond just local AI processing. The browser includes several built-in protections that work automatically without requiring additional configuration. Users get an ad blocker, tracker protection, phishing detection, DNS-over-HTTPS encryption, anti-fingerprinting technology, and a built-in VPN. The codebase itself is open-source, allowing security researchers and privacy advocates to audit how the browser handles data.

A dedicated Private mode creates a completely separate environment from regular browsing. When activated, the theme changes, the default search engine switches to DuckDuckGo, and all AI interactions lock down to local-only processing. Sigma also uses a 12-word passphrase to encrypt user profiles, called Spaces, giving users control over their data encryption.

Steps to Set Up Sigma for Maximum Privacy

• Enable Private Mode: Activate the dedicated Private mode environment to lock all AI interactions to local-only processing and switch the default search engine to DuckDuckGo for enhanced privacy.
• Save Your Encryption Passphrase: When you first open Sigma, you receive a 12-word passphrase that encrypts your Spaces (user profiles); save this as a plain text file since losing it means losing access to your encrypted data.
• Configure Local Models: In settings, select your preferred local model such as Gemma 4 E4B, Qwen 3.5, Nemotron 3, or GLM 4.7 to ensure your AI interactions stay on-device for routine tasks.
• Review Built-in Protections: Verify that the ad blocker, tracker protection, phishing detection, TLS 1.3 encryption, DNS-over-HTTPS, anti-fingerprinting, and end-to-end encrypted AI chats are enabled by default.
• Audit the Open-Source Codebase: Review the browser's open-source code or read security audits from trusted researchers to independently verify privacy claims rather than relying on vendor assurances.

How Does Sigma Compare to Existing AI Browsers?

The AI browser category has exploded in recent years. Perplexity launched Comet, OpenAI released Atlas, and Google integrated Gemini directly into Chrome's sidebar with autonomous browsing capabilities. Sigma enters this crowded space with a distinct advantage: it bundles everything needed for local AI right out of the box.

Brave's Leo AI also supports local models, but it requires users to install Ollama separately and provide their own model weights, a process that's only practical for people already familiar with running local language models. Sigma eliminates this friction by including Eclipse and other model options pre-configured, making local AI accessible to mainstream users without technical expertise.

The browser experience itself mirrors familiar interfaces. The AI Chat sidebar resembles Claude or ChatGPT, with conversation history, a library for saved chats, and projects for organizing work. Skills are accessible via slash commands, helpers via at-symbol mentions, and mode buttons let you switch between Learn, Summarize, Write, Deep Research, Analyze, and Create Image functions. Canvas Design, one of the available skills, can generate mockups and design documentation comparable to Claude Artifacts or Gemini Canvas.

What Makes Sigma Different From Cloud-First Alternatives?

The fundamental difference between Sigma and services like Perplexity or Chrome's Gemini integration comes down to data control. When you use Perplexity or cloud-based AI, your search queries and prompts travel to external servers, where they're processed and potentially logged. Sigma's local-first approach keeps that data on your device, a significant advantage for users handling sensitive information, legal documents, or proprietary business data.

The tradeoff is computational power. Local models run on your hardware, so performance depends on your device's processor and RAM. Sigma acknowledges this by allowing users to route heavier tasks to cloud models while keeping routine browsing and simple queries local. This hybrid model gives users control over the privacy-performance balance rather than forcing an all-or-nothing choice.

For users tired of the surveillance economics underlying most free AI services, Sigma represents a meaningful shift. No account creation is required for local chat, no API keys are needed, and no usage data flows to third parties. The browser works offline for basic AI tasks, and the open-source codebase means the privacy claims can be independently verified rather than taken on faith.

As the AI browser category matures, Sigma's emphasis on local processing and user control positions it as a credible alternative to Chrome and Perplexity for privacy-conscious users willing to trade some convenience for data sovereignty.