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Responsive Testing

Find the breakpoint that breaks your page

QA Proof renders your page at desktop, tablet and mobile widths, then reports layout breaks, overflowing content and touch targets that are too small to tap.

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Free plan available · No credit card required

3 viewports tested
Desktop 1440px
95
Tablet 768px
78
Mobile 390px
92
Touch targets
88

Nobody tests the tablet

Most teams check a page on their own laptop and one phone, then ship. The widths in between are where things quietly break — a nav that wraps, a table that overflows, a button too small to hit with a thumb. Users find those before you do.

How it works

1

Enter your URL

One page URL is all you need — no scripts, no device lab, no browser extensions.

2

We render three viewports

Desktop, tablet and mobile are rendered in a real browser at true device widths.

3

Review what broke

Each viewport gets its own score plus a list of layout issues with suggested media queries.

What we check at every width

Three real viewports

Desktop, tablet and mobile rendered at true device widths — not a browser window squashed with CSS.

Touch target validation

Flags any interactive element under the 44×44px minimum that guidelines require for reliable tapping.

Content overflow detection

Catches horizontal scroll, clipped text and elements pushed outside the viewport.

Media query recommendations

Suggested breakpoint rules for each issue, ready to drop into your stylesheet.

Per-viewport scoring

See at a glance which width is the weak one instead of getting one blended number.

API access

Trigger responsive checks from CI so a broken mobile layout never reaches main.

Who uses it

Frontend developers

Catch the breakpoint problems you would otherwise find by dragging the browser window around.

QA engineers

Cover three viewports on every release without maintaining a device lab.

Ecommerce teams

Most of your traffic is mobile. Make sure the checkout actually works there.

Common questions

Desktop at 1440px, tablet at 768px and mobile at 390px by default — the widths that represent the bulk of real traffic. Each is rendered in a real browser rather than simulated by resizing.
Accessibility guidelines set a 44×44px minimum for tappable elements because smaller targets cause mis-taps, especially for users with motor impairments. Small touch targets are also one of the most common mobile conversion killers.
We render in a real browser engine at true device widths, which catches layout, overflow and touch target problems. Hardware-specific behaviour like iOS Safari toolbar quirks still needs a physical device.
About 20 seconds for all three viewports.
Pages must be publicly reachable for the renderer to load them. For staging environments, allowlist our requests or expose the page at a temporary public URL.

Explore the rest of the platform

Design Fidelity Compare Figma designs against your live pages, difference by difference. Accessibility Audit WCAG 2.1 compliance checks with violation reports and fixes. Visual Regression Scheduled screenshot comparisons against approved baselines. Design Audit Design token consistency and your Design Debt Score.

Test your page across every viewport

Free plan, no credit card, three viewports in about 20 seconds.

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