Eval API

Execute code

POST /eval/{sid}

{
  "code": "result = await page.title()\nprint(result)",
  "timeout": 30000
}

Executes arbitrary Python code in a sandboxed environment with access to the session’s Playwright objects.

Sandbox globals

brow bundles patchright (a stealth-patched fork of Playwright), not playwright itself — the objects below are patchright instances, API-compatible with Playwright’s.

Name	Type	Description
page	patchright.async_api.Page	Active page
context	patchright.async_api.BrowserContext	Browser context
browser	patchright.async_api.Browser	Browser instance
state	dict	Session state (console_logs, network_requests, etc.)
pages	list	All pages in the session
asyncio	module	asyncio module
text	function	await text(selector) — inner text of the first match, or None
texts	function	await texts(selector) — inner text of every match

Response:

{
  "result": "Example Domain",
  "stdout": ""
}

result is whatever you assign to a variable named result — there’s no implicit “value of the last expression” the way a REPL works, so a bare await page.title() with no assignment returns nothing. stdout always captures anything printed with print(), whether or not you also set result.

Examples

Get page title:

result = await page.title()

Extract all links:

links = await page.evaluate("""
  () => Array.from(document.querySelectorAll('a[href]'))
        .map(a => ({text: a.innerText.trim(), href: a.href}))
""")
result = links

Inject a cookie:

await context.add_cookies([{
  "name": "session",
  "value": "abc123",
  "domain": "example.com",
  "path": "/"
}])

Grant permissions:

await context.grant_permissions(["geolocation"])
await page.set_geolocation({"latitude": 48.1, "longitude": 17.1})

!!! warning “No stdout return by default” eval does not return printed output unless you use print() explicitly and check stdout. Side effects (cookies set, navigation triggered) take effect immediately but aren’t reported unless you capture them in result.

!!! note “Async functions” The sandbox is async — you can await any Playwright coroutine directly.

!!! tip “Long jobs: raise timeout, don’t batch” A timed-out call still returns whatever stdout was printed before the cutoff, so raising timeout for a long job loses less than staging progress across many short calls.

For a reusable version of the same sandbox — a .py file executed once instead of an inline code string — see brow run.