Mobile-Friendly Test

Mobile-Friendly Test reads a page's viewport configuration and responsive-image markup and reports whether it is set up to lay out correctly on a phone.

The verdict turns on one thing: a viewport meta tag carrying width=device-width. Without it the test fails outright, because a phone will lay the page out at desktop width whatever the CSS says. The rest are warnings rather than failures — initial-scale=1 not declared, user-scalable=no disabling pinch-to-zoom, which is an accessibility problem rather than a rendering one, and images with no srcset or <picture> around them. This reads markup only: it does not render the page at a phone width, so it cannot see an element that overflows the screen or a tap target that is too small to hit.

Entering a URL has ShortTrick's server fetch the page HTML, so the entry in that site's logs is ours, made with our own user agent and nothing taken from your browser. No rendering happens on either machine, and the HTML is discarded after parsing. Pasting the markup makes no request at all.

Checking a new template declares a viewport before launch, catching a user-scalable=no left behind from a prototype, confirming responsive images are in place on an image-heavy page, and auditing a legacy page against mobile-first indexing.

Also known as: responsive website tester · check mobile usability