Your code is fine. Does it work on a phone?

Most launch checklists never open the site on a phone until it's too late. The Mobile Readiness scanner reads your source for the patterns that break mobile layout, before you deploy, offline, on every scan. It is the source-side complement to the Pro Live Site Auditor, which measures the real result on your deployed URL.

What it catches

Nine static checks for the things that make a page unusable, cramped, or overflowing on a small screen:

Viewport meta missing Zoom disabled Images that stretch Fixed-width overflow min-width overflow 100vw scrollbar Inline fixed width No @media breakpoints Tiny body text

The three that bite most

1. A missing viewport meta

Without <meta name="viewport" content="width=device-width, initial-scale=1">, a mobile browser renders your page at a desktop width and shrinks the whole thing to fit. Text becomes unreadable and nothing adapts. It is the single most common reason a site is unusable on a phone, and it is a one-line fix, so this check is the only one rated High.

2. Images that scale width but not height

An <img> rule with width: 100% but no height: auto keeps the image's HTML height and stretches it vertically as the width shrinks. On a phone the picture is distorted and tall. It is a subtle bug that looks fine on desktop and wrong on mobile.

3. Fixed widths that overflow

A container pinned to width: 1200px (or a min-width, which can't even shrink) is wider than a phone screen, so the page scrolls sideways and content is cut off at the edges. The scanner flags fixed pixel widths on layout containers, inline styles, and min-width, while leaving desktop @media breakpoints alone.

The honest line

This is a readiness check, not a guarantee. Static analysis catches patterns, not the rendered result. The measured outcome (does it actually reflow, what the layout looks like on a real device) is what the Pro Live Site Auditor gives you. These findings are quality signals: they sharpen your grade but never gate the Ship-It security verdict.

How it fits the workflow

Free and offline, on every scan. No URL needed. It reads your HTML, CSS, and components locally, so you see mobile problems before you deploy.
Precision over recall. It stays silent on well-built responsive pages (viewport present, images with height:auto, real breakpoints) and only fires on the clear patterns. No nagging.
Pairs with the Live Auditor. Source scan catches the pattern early; the Pro Live Site Auditor confirms the real behaviour on your deployed site.

How to fix what it finds

Add the viewport meta to every page's <head>, and remove user-scalable=no / maximum-scale=1 so users can zoom.
Give scaled images height: auto (or an aspect-ratio) alongside max-width: 100%.
Swap fixed width for max-width plus width: 100%, and lower any large min-width on small screens.
Add @media breakpoints that stack columns and tighten spacing, and keep body text at 16px or more.

IOnclad reports patterns it can see in source. It is not a device lab or a guarantee that a page renders perfectly everywhere.

See your mobile problems before your users do.

Scan your code in under a minute, offline. Nothing leaves your machine.

Try the Browser Scanner → Download for Windows