steero

Disclaimer. steero is provided AS IS, without warranty of any kind, express or implied. Use it entirely at your own risk. It launches and controls web browsers and can act on any site you point it at. The authors accept no liability for data loss or corruption, damage to hardware, systems that will not start, business interruption, or any consequential damages. You are responsible for checking what you automate, keeping tested backups, and being authorised to act on the sites and accounts you drive. steero is not certified for regulated, forensic, safety-critical or high-assurance use. See DISCLAIMER.md. The LICENSE (MIT) is the governing text and prevails wherever it and this summary differ.

Typed, async-first Python driver for the stock Chrome and Firefox you already have, over the W3C WebDriver BiDi standard.

• No patched browsers. One standard protocol drives both. Firefox needs no driver; Chrome uses chromedriver or, with backend="chromium-bidi", nothing extra.
• Auto-waiting before every action, with errors that say which check failed.
• Typed end to end. The protocol layer is generated from the specification.
• Async core, sync API, pytest plugin with failure artifacts, self-healing locators, and an MCP server so AI agents can drive Firefox too.
• Leaves nothing behind. No orphaned browser processes, no leaked profiles.

Install

pip install steero
steero doctor

Example

import asyncio
import steero
from steero import expect

async def main() -> None:
    async with steero.launch("firefox") as browser:
        page = await browser.new_page()
        await page.goto("https://example.com/login")
        await page.get_by_label("User name").fill("ada")
        await page.get_by_role("button", name="Sign in").click()
        await expect(page.get_by_role("status")).to_have_text("Welcome, ada")

asyncio.run(main())

Sync, with pytest:

from steero.sync_api import expect

def test_login(steero_page):
    steero_page.goto("https://example.com/login")
    steero_page.get_by_label("User name").fill("ada")
    steero_page.get_by_role("button", name="Sign in").click()
    expect(steero_page.get_by_role("status")).to_have_text("Welcome, ada")

pytest --steero-browser chrome --steero-browser firefox

What is in the box

Status

1.0.0rc3. 1.0.0rc2 was tested on Windows and Linux with Chrome 155 and Firefox 158, including a 279-test hard-controls suite (ControlLab) on each browser configuration; rc3 adds error-page navigation and listener access, tested on Windows. See the policy for versioning, deprecation and supported browsers, and the changelog.

Documentation

The guides live in docs/: getting started, locators, auto-waiting, network, contexts, the pytest plugin, self-healing, the MCP server, migrating from Selenium or Playwright, and an honest comparison.

Contributing

Contributions are welcome: see CONTRIBUTING.md, the Code of Conduct and GOVERNANCE.md. Report security problems privately, as described in SECURITY.md.

License

MIT - see LICENSE.