Playwright

Playwright is a browser automation library from Microsoft. Kernel browsers speak the Chrome DevTools Protocol (CDP), so you can point an existing Playwright script at a cloud browser by swapping your launch call for a connectOverCDP to the session’s cdp_ws_url — no other code changes.

If you don’t need a local Playwright install and want your code to run co-located with the browser, use Playwright Execution instead. It runs the same Playwright API inside the browser’s VM and returns values back to your agent. This page covers connecting a Playwright client you run yourself.

Install

npm install playwright @onkernel/sdk

pip install playwright kernel

Create a browser and connect

Create a Kernel browser, then connect Playwright to its cdp_ws_url. Kernel opens a context and page for you — grab them from the connected browser rather than calling newContext.

import { chromium } from 'playwright';
import Kernel from '@onkernel/sdk';

const kernel = new Kernel();

const kernelBrowser = await kernel.browsers.create();
console.log('Live view:', kernelBrowser.browser_live_view_url);

const browser = await chromium.connectOverCDP(kernelBrowser.cdp_ws_url);
const context = browser.contexts()[0];
const page = context.pages()[0];

await page.goto('https://onkernel.com');
console.log(await page.title());

await browser.close();
await kernel.browsers.deleteByID(kernelBrowser.session_id);

import asyncio
from kernel import Kernel
from playwright.async_api import async_playwright

kernel = Kernel()

async def main():
    kernel_browser = kernel.browsers.create()
    print("Live view:", kernel_browser.browser_live_view_url)

    async with async_playwright() as playwright:
        browser = await playwright.chromium.connect_over_cdp(kernel_browser.cdp_ws_url)
        context = browser.contexts[0]
        page = context.pages[0]

        await page.goto("https://onkernel.com")
        print(await page.title())

        await browser.close()

    kernel.browsers.delete_by_id(kernel_browser.session_id)

asyncio.run(main())

Configure the viewport

Set the viewport when you create the browser, not through Playwright. Playwright’s setViewportSize is a no-op over a CDP connection — the window size is fixed at browser creation. See Viewports for supported dimensions and refresh rates.

const kernelBrowser = await kernel.browsers.create({
  viewport: { width: 1280, height: 720 },
});

kernel_browser = kernel.browsers.create(
    viewport={"width": 1280, "height": 720},
)

Stealth mode

Create the browser with stealth: true to harden it against bot detection. The connection is unchanged — you still connect Playwright to cdp_ws_url.

const kernelBrowser = await kernel.browsers.create({ stealth: true });

kernel_browser = kernel.browsers.create(stealth=True)

See stealth mode for what it changes. For the strongest anti-detection posture, prefer computer controls or Playwright Execution — a direct CDP connection carries a fingerprint that co-located control avoids.

Why run Playwright on Kernel

No local browser management. No Chromium download or version pinning on your machine — the browser runs in Kernel’s cloud.
Persistent state. Keep cookies and login state across runs with Profiles.
Scale out. Launch many sessions in parallel instead of contending for one local browser.
Debuggable. Watch any session in real time with live view.
No code rewrite. Existing Playwright scripts work as-is once you swap the launch for connectOverCDP.

Next steps

Playwright Execution — run Playwright inside the browser VM with no local install
Live view — watch and debug your sessions
Stealth mode — avoid bot detection
Terminating sessions — clean up browsers when you’re done

Overview

Working with your browser

deploying your agent

Agent Skills

Integrations

Migrations

Community

Info

Install

Create a browser and connect

Configure the viewport

Stealth mode

Why run Playwright on Kernel

Next steps

​Install

​Create a browser and connect

​Configure the viewport

​Stealth mode

​Why run Playwright on Kernel

​Next steps

Install

Create a browser and connect

Configure the viewport

Stealth mode

Why run Playwright on Kernel

Next steps