Nanobrowser is an open-source Chrome extension that transforms your browser into an AI-powered web automation engine. Designed for developers, researchers, and power users, it eliminates the need for expensive SaaS tools like OpenAI Operator by running multi-agent workflows entirely in-browser using your own LLM API keys. It solves the problem of vendor lock-in and privacy risks in AI automation by keeping all data and credentials local.
Built with TypeScript and leveraging Browser Use, Puppeteer, and LangChain.js, Nanobrowser supports multiple LLM providers including OpenAI, Anthropic, Gemini, Ollama, and custom OpenAI-compatible endpoints. It deploys as a Chrome/Edge extension with optional local builds via Node.js and pnpm, offering full transparency and control over automation logic without cloud intermediaries.
What You Get
- Multi-agent System - Specialized AI agents (Planner, Navigator, Validator) collaborate to execute complex web tasks like research, data extraction, and form filling, with each agent handling distinct roles in the workflow.
- Interactive Side Panel - A real-time chat interface within the browser sidebar displays agent status, task progress, and outputs, enabling direct user interaction during automation.
- Task Automation - Automate repetitive web tasks across any site (e.g., extracting headlines, scraping product data, monitoring GitHub trends) using natural language prompts without writing code.
- Follow-up Questions - After a task completes, users can ask contextual follow-up questions to refine results, such as “What’s the average price of these speakers?” without re-initiating the entire workflow.
- Conversation History - Persistent storage of past interactions allows users to review, reuse, or modify previous automation sessions directly from the extension panel.
- Multiple LLM Support - Configure different LLMs per agent (e.g., Claude Sonnet 4 for Planner, Gemini 2.5 Flash for Navigator) and connect to OpenAI, Anthropic, Gemini, Ollama, Groq, Cerebras, Llama, or custom OpenAI-compatible APIs.
Common Use Cases
- Researching market trends - A product manager uses Nanobrowser to extract top 10 trending GitHub repositories in Python with star counts and recent commits, automating what would otherwise require manual browsing and note-taking.
- E-commerce price monitoring - A consumer uses Nanobrowser to find portable Bluetooth speakers on Amazon under $50 with water resistance and 10+ hour battery life, then compares specs across listings automatically.
- News aggregation for professionals - A journalist runs a daily automation to pull the top 10 headlines from TechCrunch, summarize them, and save the results to a local file for morning briefings.
- Local LLM-powered automation - A privacy-conscious developer runs Qwen3-30B or Mistral Small 24B via Ollama locally to automate web tasks without sending any data to external servers, ensuring full data sovereignty.
Under The Hood
Architecture
- Monorepo structure with clear separation between UI, shared logic, and browser extension modules using pnpm workspaces
- Dependency injection achieved through TypeScript interfaces and workspace-relative imports, enabling modular, testable components without external frameworks
- Chrome API abstractions are isolated in extension-specific modules, decoupling React UI from browser-specific logic
- Turbo monorepo build system enforces incremental builds and task dependency graphs for predictable workflows
- Shared ESLint and TypeScript configurations enforce consistent code quality across all packages
Tech Stack
- React 18 with TypeScript and Vite form the core frontend stack, optimized for Chrome extension UI development
- Tailwind CSS and PostCSS enable utility-first styling with custom configurations for side panels and extensions
- Turbo orchestrates parallelized builds across workspace packages, improving development efficiency
- ESLint with airbnb-typescript and Tailwind plugins ensures strict code quality standards
- Puppeteer-core and Chrome extension APIs are integrated for browser automation and extension functionality
- PNPM manages dependencies with workspace links and overrides for precise version control
Code Quality
- Extensive test coverage includes unit and integration tests for security-critical paths like sanitization and threat detection
- Clear separation of concerns between guardrails, sanitization utilities, and message processing layers
- Robust error handling with custom threat classifications and structured outputs to prevent silent failures
- Consistent naming conventions and strong TypeScript typing reduce runtime errors and improve maintainability
- Comprehensive linting and edge case validation ensure reliability in complex web contexts
What Makes It Unique
- Implements Manifest V3-compatible analytics with strict CSP compliance, avoiding external script loading
- Features a custom HMR plugin for content scripts, enabling hot-reloading despite Chrome extension limitations
- Builds content scripts as IIFE bundles to ensure isolation in arbitrary web environments
- Uses pattern-based error classification with regex heuristics to categorize failures without external logging
- Employs Vite’s build-time injection to enable dynamic, environment-aware configuration across extension components