[opensourcedex]

nanobrowser is a free, open source browsers & extensions project written in TypeScript and released under Apache-2.0. It has 13,809 GitHub stars, 1,456 forks and 81 open issues, and was last pushed 1 months ago. On this registry it ranks #30 of 65 tracked projects in Browsers & Extensions, with 5 head-to-head comparisons available. It gained 8 stars over the last 3 tracked days.

What is nanobrowser?

Nanobrowser is an open-source Chrome extension for AI-powered web automation that runs multi-agent workflows inside your own browser using your own LLM API key, built for people who want Operator-style browser agents without a subscription.

What it is

Nanobrowser is an open-source AI web automation tool that runs as a browser extension. It is written in TypeScript under the Apache-2.0 licence, and it lives in the Chrome and Edge extension ecosystem rather than as a hosted service or standalone application. Work is handled by a multi-agent system: a Planner agent decomposes the task and a Navigator agent drives the page, with the Planner able to self-correct when it hits obstacles and dynamically instruct the Navigator to adjust its approach. Everything runs locally in the browser, and the models behind the agents are the ones the user configures.

The concrete problem it solves is the cost and opacity of commercial browser agents. It is positioned as a free alternative to OpenAI Operator, which the README cites at a $200/month price tag. Rather than a subscription that hides which model runs and where data goes, Nanobrowser keeps the API keys with the user and lets a different model be assigned to each agent. The README states support for OpenAI, Anthropic, Gemini, Ollama, Groq, Cerebras, Llama and custom OpenAI-Compatible providers, with more planned.

Key capabilities

  • Multi-agent system with separate roles: a Planner that breaks down the task and a Navigator that acts, where the Planner can self-correct and re-instruct the Navigator mid-task.
  • Bring-your-own-key configuration: API keys are added under the Settings icon in the sidebar, and a model can be chosen per agent.
  • Provider coverage for OpenAI, Anthropic, Gemini, Ollama, Groq, Cerebras, Llama and custom OpenAI-Compatible endpoints.
  • Interactive side panel that serves as the chat interface and reports real-time status while a task runs.
  • Task automation across websites for repetitive browser work, plus contextual follow-up questions about completed tasks.
  • Conversation history that can be reviewed and managed.
  • Chrome and Edge are officially supported with full features; Firefox, Safari and other Chromium variants such as Opera and Arc are not supported.

Who uses it and how

  • Users who already hold LLM API keys and want browser automation billed per token through their own provider account instead of a flat subscription.
  • Privacy-conscious users who want credentials to stay in the local browser rather than be shared with a cloud automation service.
  • Individuals and teams that mix providers per agent, for example a local Ollama model for navigation and a stronger hosted model for planning.
  • Users running repetitive multi-step web workflows who want to follow progress and ask follow-up questions in the side panel.
  • Chrome and Edge users specifically, since the README recommends those two browsers for guaranteed compatibility.

Getting started

Install Nanobrowser free from the Chrome Web Store and confirm the prompt, then open the sidebar from the toolbar, click the Settings icon, add LLM API keys, and assign models to the Navigator and Planner agents. For the latest features the README also documents a manual installation of the newest version, noting that the Chrome Web Store build may be delayed by the review process.

How it compares

Against OpenAI Operator, the contrast is cost and control: Nanobrowser charges no subscription fee and instead bills only what the user's own API keys consume. It is Apache-2.0 licensed and fully open source, so the automation path is inspectable rather than a black box, while Operator is a closed hosted product. Data ownership follows the same line, because Nanobrowser runs in the local browser and keeps credentials there rather than routing the session through a vendor cloud.

When to use it — and when not to

Choose it when you are willing to manage your own LLM provider accounts, keys and per-token costs, and when you work in Chrome or Edge. Do not choose it if you need Firefox, Safari or another Chromium variant, since support is explicitly absent, and do not expect a managed service that supplies models for you. Two practical caveats: the Chrome Web Store version can lag the repository while under review, and the project carried 81 open issues at the time of writing.

project readme (upstream, from github) — read inline

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🌐 Nanobrowser

Nanobrowser is an open-source AI web automation tool that runs in your browser. A free alternative to OpenAI Operator with flexible LLM options and multi-agent system.

⬇️ Get Nanobrowser from Chrome Web Store for free

👏 Join the community in Discord | X

🌟 Loving Nanobrowser? Give us a star and help spread the word!

❤️ Support the project by sponsoring us - every contribution helps keep Nanobrowser free and open source!

Nanobrowser Demo GIF

Nanobrowser's multi-agent system analyzing HuggingFace in real-time, with the Planner intelligently self-correcting when encountering obstacles and dynamically instructing the Navigator to adjust its approach—all running locally in your browser.

🔥Why Nanobrowser?

Looking for a powerful AI browser agent without the $200/month price tag of OpenAI Operator? Nanobrowser , as a chrome extension, delivers premium web automation capabilities while keeping you in complete control:

  • 100% Free - No subscription fees or hidden costs. Just install and use your own API keys, and you only pay what you use with your own API keys.
  • Privacy-Focused - Everything runs in your local browser. Your credentials stay with you, never shared with any cloud service.
  • Flexible LLM Options - Connect to your preferred LLM providers with the freedom to choose different models for different agents.
  • Fully Open Source - Complete transparency in how your browser is automated. No black boxes or hidden processes.

Note: We currently support OpenAI, Anthropic, Gemini, Ollama, Groq, Cerebras, Llama and custom OpenAI-Compatible providers, more providers will be supported.

📊 Key Features

  • Multi-agent System: Specialized AI agents collaborate to accomplish complex web workflows
  • Interactive Side Panel: Intuitive chat interface with real-time status updates
  • Task Automation: Seamlessly automate repetitive web automation tasks across websites
  • Follow-up Questions: Ask contextual follow-up questions about completed tasks
  • Conversation History: Easily access and manage your AI agent interaction history
  • Multiple LLM Support: Connect your preferred LLM providers and assign different models to different agents

🌐 Browser Support

Officially Supported:

  • Chrome - Full support with all features
  • Edge - Full support with all features

Not Supported:

  • Firefox, Safari, and other Chromium variants (Opera, Arc, etc.)

Note: While Nanobrowser may function on other Chromium-based browsers, we recommend using Chrome or Edge for the best experience and guaranteed compatibility.

🚀 Quick Start

  1. Install from Chrome Web Store (Stable Version):

Important Note: For latest features, install from "Manually Install Latest Version" below, as Chrome Web Store version may be delayed due to review process.

  1. Configure Agent Models:
    • Click the Nanobrowser icon in your toolbar to open the sidebar
    • Click the Settings icon (top right)
    • Add your LLM API keys
    • Choose which model to use for different agents (Navigator, Planner)

🔧 Manually Install Latest Version

To get the most recent version with all the latest features:

  1. Download

    • Download the latest nanobrowser.zip file from the official Github release page.

  2. Install:

    • Unzip nanobrowser.zip.
    • Open chrome://extensions/ in Chrome
    • Enable Developer mode (top right)
    • Click Load unpacked (top left)
    • Select the unzipped nanobrowser folder.

  3. Configure Agent Models

    • Click the Nanobrowser icon in your toolbar to open the sidebar
    • Click the Settings icon (top right).
    • Add your LLM API keys.
    • Choose which model to use for different agents (Navigator, Planner)

  4. Upgrading:

    • Download the latest nanobrowser.zip file from the release page.
    • Unzip and replace your existing Nanobrowser files with the new ones.
    • Go to chrome://extensions/ in Chrome and click the refresh icon on the Nanobrowser card.

🛠️ Build from Source

If you prefer to build Nanobrowser yourself, follow these steps:

  1. Prerequisites:

    • Node.js (v22.12.0 or higher)
    • pnpm (v9.15.1 or higher)

  2. Clone the Repository:

    git clone https://github.com/nanobrowser/nanobrowser.git
cd nanobrowser

  3. Install Dependencies:

    pnpm install

  4. Build the Extension:

    pnpm build

  5. Load the Extension:

    • The built extension will be in the dist directory
    • Follow the installation steps from the Manually Install section to load the extension into your browser

  6. Development Mode (optional):

    pnpm dev

🤖 Choosing Your Models

Nanobrowser allows you to configure different LLM models for each agent to balance performance and cost. Here are recommended configurations:

Better Performance

  • Planner: Claude Sonnet 4
    • Better reasoning and planning capabilities
  • Navigator: Claude Haiku 3.5
    • Efficient for web navigation tasks
    • Good balance of performance and cost

Cost-Effective Configuration

  • Planner: Claude Haiku or GPT-4o
    • Reasonable performance at lower cost
    • May require more iterations for complex tasks
  • Navigator: Gemini 2.5 Flash or GPT-4o-mini
    • Lightweight and cost-efficient
    • Suitable for basic navigation tasks

Local Models

  • Setup Options:

    • Use Ollama or other custom OpenAI-compatible providers to run models locally
    • Zero API costs and complete privacy with no data leaving your machine

  • Recommended Models:

  • Prompt Engineering:

    • Local models require more specific and cleaner prompts
    • Avoid high-level, ambiguous commands
    • Break complex tasks into clear, detailed steps
    • Provide explicit context and constraints

Note: The cost-effective configuration may produce less stable outputs and require more iterations for complex tasks.

Tip: Feel free to experiment with your own model configurations! Found a great combination? Share it with the community in our Discord to help others optimize their setup.

💡 See It In Action

Here are some powerful tasks you can accomplish with just a sentence:

  1. News Summary:

    "Go to TechCrunch and extract top 10 headlines from the last 24 hours"

  2. GitHub Research:

    "Look for the trending Python repositories on GitHub with most stars"

  3. Shopping Research:

    "Find a portable Bluetooth speaker on Amazon with a water-resistant design, under $50. It should have a minimum battery life of 10 hours"

🛠️ Roadmap

We're actively developing Nanobrowser with exciting features on the horizon, welcome to join us!

Check out our detailed roadmap and upcoming features in our GitHub Discussions.

🤝 Contributing

We need your help to make Nanobrowser even better! Contributions of all kinds are welcome:

  • *Share Prompts & Use Cases

readme truncated — read the full docs on github

Frequently asked questions

Is nanobrowser free to use?

nanobrowser is open source under the Apache-2.0 licence. There is no licence fee and no seat count — you can self-host it or, where the project offers one, pay a vendor for a managed version instead.

What does nanobrowser do?

Open-Source Chrome extension for AI-powered web automation. Run multi-agent workflows using your own LLM API key. Alternative to OpenAI Operator.

What is nanobrowser written in?

nanobrowser is primarily written in TypeScript. Its source is publicly available at https://github.com/nanobrowser/nanobrowser, and it has 13,809 GitHub stars.