> ## Documentation Index
> Fetch the complete documentation index at: https://docs.microsandbox.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Browser Use

> Run an AI browser agent with isolated Chromium inside a microVM

[Browser Use](https://github.com/browser-use/browser-use) turns a task into browser actions. This example runs both the agent and Chromium inside one isolated microsandbox.

<Note>
  The browser image is large. Its first pull and Python package install can take a few minutes. Use a [snapshot](/examples/sandboxing/warm-workers) to avoid repeating that setup.
</Note>

## Run Browser Use

<Steps>
  <Step title="Create the agent">
    Save this as `browser-use-task.py`:

    ```python theme={null}
    import asyncio
    import os

    from browser_use import Agent, BrowserProfile, BrowserSession, ChatBrowserUse


    async def main() -> None:
        browser = BrowserSession(
            browser_profile=BrowserProfile(
                headless=True,
                executable_path=os.environ["CHROME_PATH"],
                args=["--no-sandbox", "--disable-dev-shm-usage"],
                enable_default_extensions=False,
                user_data_dir=None,
            )
        )
        agent = Agent(
            task="Return the title of https://example.com",
            llm=ChatBrowserUse(model="bu-2-0"),
            browser_session=browser,
        )
        history = await agent.run(max_steps=3)
        print(history.final_result())
        await browser.kill()


    asyncio.run(main())
    ```
  </Step>

  <Step title="Start the sandbox">
    Export a [Browser Use API key](https://cloud.browser-use.com/new-api-key), then run the task. The secret stays on the host and can only be substituted into requests to Browser Use's model endpoint.

    <CodeGroup>
      ```sh macOS & Linux theme={null}
      export BROWSER_USE_API_KEY="your-key"

      msb run --name browser-use-task --replace \
        --cpus 2 --memory 4G --root-disk 10G \
        --secret "BROWSER_USE_API_KEY@llm.api.browser-use.com" \
        --copy-file ./browser-use-task.py:/root/browser-use-task.py \
        mcr.microsoft.com/playwright/python:v1.61.0-noble -- sh -lc '
          apt-get update -qq && apt-get install -y -qq libnss3-tools &&
          mkdir -p "$HOME/.pki/nssdb" &&
          certutil -d sql:"$HOME/.pki/nssdb" -N --empty-password &&
          certutil -d sql:"$HOME/.pki/nssdb" -A -n microsandbox-egress -t "C,," -i /.msb/tls/ca.pem &&
          pip install --disable-pip-version-check browser-use==0.13.10 &&
          CHROME_PATH="$(find /ms-playwright -path "*/chrome-linux/chrome" -type f | head -n 1)" \
            python /root/browser-use-task.py
        '
      ```

      ```powershell Windows theme={null}
      $env:BROWSER_USE_API_KEY = "your-key"

      msb run --name browser-use-task --replace `
        --cpus 2 --memory 4G --root-disk 10G `
        --secret "BROWSER_USE_API_KEY@llm.api.browser-use.com" `
        --copy-file ./browser-use-task.py:/root/browser-use-task.py `
        mcr.microsoft.com/playwright/python:v1.61.0-noble -- sh -lc '
          apt-get update -qq && apt-get install -y -qq libnss3-tools &&
          mkdir -p "$HOME/.pki/nssdb" &&
          certutil -d sql:"$HOME/.pki/nssdb" -N --empty-password &&
          certutil -d sql:"$HOME/.pki/nssdb" -A -n microsandbox-egress -t "C,," -i /.msb/tls/ca.pem &&
          pip install --disable-pip-version-check browser-use==0.13.10 &&
          CHROME_PATH="$(find /ms-playwright -path "*/chrome-linux/chrome" -type f | head -n 1)" \
            python /root/browser-use-task.py
        '
      ```
    </CodeGroup>

    The agent prints its final result and exits. The Browser Use browser session uses the Chromium already included in the image, so it does not download a second browser.

    <Warning>
      `--secret` routes egress through microsandbox's TLS-terminating proxy. Chromium reads its own NSS
      store, not `SSL_CERT_FILE` or `NODE_EXTRA_CA_CERTS`, so without the `certutil` step above every
      page load fails with `net::ERR_CERT_AUTHORITY_INVALID` and the agent burns steps clicking through
      the interstitial. Importing `/.msb/tls/ca.pem` into `$HOME/.pki/nssdb` is what makes navigation clean.
    </Warning>
  </Step>

  <Step title="Clean up">
    Remove the stopped sandbox and unset the API key:

    <CodeGroup>
      ```sh macOS & Linux theme={null}
      msb rm -f browser-use-task
      unset BROWSER_USE_API_KEY
      ```

      ```powershell Windows theme={null}
      msb rm -f browser-use-task
      Remove-Item Env:BROWSER_USE_API_KEY
      ```
    </CodeGroup>
  </Step>
</Steps>

## Reference

* [Browser Use Python quickstart](https://docs.browser-use.com/open-source/introduction)
* [Microsandbox secrets](/sandboxes/secrets)
* [Microsandbox snapshots](/examples/sandboxing/warm-workers)