Make it possible to emulate viewport sizes

[syntaxseed]

Inspect.dev version: 1.09 on Ubuntu 20.04.

I've poured all over the application, the online inspect.dev docs and searched online.

I'm inspecting a webview inside an iOS application.

Is there a way to change the viewport size aka simulate different devices sizes in inspect.dev? The app running on my iPad won't change, but I want to see what my webview will do if I had it on a smaller devices for example.

Chrome devtools allows this in the browser.

This might be more of a feature request.

[auchenberg]

Not at the moment, as Apple does not support this in Webkit on iOS. Best proxy is to use Safari on your desktop.

[auchenberg]

Verified again against Safari on an iPhone 17 Pro simulator running iOS 26.5. The page reported a 402×714 CSS viewport before the test. Sending Emulation.setDeviceMetricsOverride for 320×480 reached WebKit, which returned Page.setScreenSizeOverride was not found; the page remained 402×714 and its media-query result did not change.

This is an upstream WebKit/iOS limitation, not an Inspect UI gap. WebKit compiles Page.setScreenSizeOverride out on Cocoa platforms, so Inspect cannot provide real viewport emulation for an iOS Safari/WebView target. The practical alternatives remain testing the intended simulator/device size or using desktop Safari responsive design mode. I have added the upstream label and am leaving this open to track any future WebKit capability.