Check Your Website at Common Mobile Screen Sizes
Responsive websites need to work across many viewport widths rather than on one specific phone. SEO Mentor includes presets for compact phones, common iPhone and Android dimensions, larger phones and tablets, plus a custom viewport option for testing your own width and height.
What the Mobile Website Test Checks
The automated analysis reviews public page signals that can affect mobile presentation, including the viewport meta tag, responsive media-query signals, large fixed-width declarations, responsive image hints, unusually small inline font sizes and horizontal-overflow masking. These checks are evidence for review rather than a substitute for using the page yourself.
Visual Responsive Preview
The device frame loads the submitted website at the selected CSS viewport dimensions. Use portrait and landscape modes to inspect navigation, text wrapping, forms, buttons, images and page sections at different widths. The preview represents viewport sizing; it does not claim to emulate the exact browser engine, hardware, pixel density or operating system of a physical phone.
Why Some Websites Cannot Appear in the Preview
Websites can intentionally prevent other domains from embedding their pages with X-Frame-Options or Content-Security-Policy frame-ancestors directives. SEO Mentor does not bypass those security controls. When embedding is blocked, the tool still reports the mobile-readiness signals it can obtain from the site's public HTML and tells you why the visual preview may not load.
Mobile SEO and User Experience
A page that technically fits a narrow viewport can still be difficult to use. Review whether important text is readable without zooming, navigation is usable, controls are easy to tap, forms fit the screen, images scale correctly and content does not disappear beyond the viewport. Test important templates rather than assuming one successful page represents the entire website.
Free Mobile Website Testing
This tool is free to use without registration, subscriptions or credits. It analyzes public website information and provides a responsive preview without claiming access to proprietary device-lab or search-engine testing data.