Window and display size - Driver

Both fields take WIDTHxHEIGHT, width 320 to 16384, height 200 to 16384.

Field	What it sets	Notes
`windowSize`	The outer Chrome window, what the page sees as `window.outerWidth/Height`.	Default depends on the machine.
`displaySize`	The virtual display the window sits on.	Leave it alone unless a site needs a screen larger than the window.

{ "windowSize": "1920x1040", "displaySize": "1920x1080" }

const session = await createSession({ windowSize: "1920x1040" });

session = create_session(windowSize="1920x1040")

Sizes people actually use

`windowSize`	Looks like
`1920x1040`	Full HD desktop with a taskbar
`1536x864`	Scaled 1080p laptop
`1440x900`	13-inch MacBook
`1366x768`	Budget laptop
`390x844`	Phone-sized window (still desktop Chrome)

Pick a size the session’s machine would plausibly have. A windowSize larger than the display is clamped.

Resizing after connecting

Set the size on create. page.setViewportSize (Playwright) and page.setViewport (Puppeteer) resize only the content area and leave outerWidth alone, a mismatch sites look for. Puppeteer applies an 800x600 viewport on connect unless you pass defaultViewport: null, so always pass it.