Limits & Billing

Billing

Browser API sessions are billed at 1 credit per 2 minutes, rounded up. A session that lasts 3 minutes costs 2 credits. A session that lasts 4 minutes 1 second also costs 2 credits (you're billed at the start of each 2-minute window).

Limits

Avoiding the idle timeout

The connection is closed if your script is silent for about 2 minutes. Long workflow pauses (MFA wait, slow API polls, OAuth callbacks) need a keepalive — call any cheap browser API every ~60 seconds:

import asyncio

# during a long wait...
while waiting_for_mfa():
    await page.evaluate("() => 0")  # cheap keepalive
    await asyncio.sleep(60)

Playwright's page.wait_for_function() and page.wait_for_selector() also keep the session alive while they're polling — preferred for any "wait until X appears" loop.

The cleanest practice is browser.close() as soon as you're done — don't leave idle connections open just because you can.

Not supported

• Selenium / ChromeDriver — only CDP-native clients (Playwright, Puppeteer, chromedp) are supported.

Error responses

Authentication and capacity errors come back as standard HTTP responses before the WebSocket upgrade, so your CDP client receives them as connection failures. Saved-session errors (404 / 409 / 422) are raised after the upgrade and arrive as a WebSocket close frame with code 1008 whose reason is "<status>: <json body>", e.g. 404: {"error": "session not found, not yet saved, or in use", ...} — Playwright surfaces it in the connectOverCDP error message.