Mobile-Friendly Test

The Mobile-Friendly Test is a free tool that inspects any public page and checks the underlying signals that determine whether it actually adapts to a mobile screen — the viewport meta tag, whether the CSS includes responsive breakpoints, whether images use srcset for right-sized delivery, and whether the page depends on unsupported legacy plugins like Flash. Instead of a vague pass or fail, you get a clear breakdown of exactly which of those signals are present, missing, or misconfigured.

It exists because mobile traffic makes up the majority of visits for most sites, and a page that looks fine on a desktop monitor can be genuinely broken on a phone — text too small to read without zooming, a layout that forces horizontal scrolling, or images that load at full desktop resolution and slow everything down. Running this check surfaces exactly which of those problems apply to a given page, on your own site or a competitor's, without needing to test on a physical device.

When you submit a URL, the tool fetches the page's live HTML and checks for the viewport meta tag and its configured values, scans the linked and inline CSS for @media breakpoint rules, checks <img> tags for srcset and sizes attributes, and looks for markup tied to unsupported legacy plugins. Each of these checks is evaluated independently and reported as a pass, warning, or issue, contributing to an overall mobile-friendliness score.

This is a static analysis of the page's HTML and CSS, not a rendered, device-simulated screenshot the way Google's own Mobile-Friendly Test produces — but it checks the same underlying signals that determine whether a page actually adapts to mobile screens. It reflects the page's response at the moment you run the check and does not execute JavaScript, so styles or markup injected purely client-side may not be captured.

• Set the viewport tag correctly on every page. width=device-width, initial-scale=1 is the baseline for any mobile-friendly page — without it, mobile browsers render at a fixed desktop width and zoom out to fit.
• Use CSS media query breakpoints so layouts adapt. @media (max-width: ...) rules let content reflow to narrower screens instead of forcing visitors to zoom and scroll sideways to read it.
• Serve right-sized images with srcset. It lets mobile devices download a smaller image instead of the same full desktop-sized file, saving real bandwidth and load time on every page view.
• Never disable pinch-to-zoom with user-scalable=no. It can make a page feel more app-like, but it actively hurts accessibility for visually impaired visitors who rely on zooming to read comfortably.