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How-To SessionComplexity: LowNo CodingWebsite QA

How to Test Your Website for Mobile and Desktop Browsers

Confidence, not perfection

A site can look perfect on one screen and break on another.

Most visitors arrive on mobile, so a quick check is worth it.

This guide uses free tools available to everyone.

Quick Path

  • Use your browser’s responsive preview to simulate a phone, tablet, and desktop.
  • Rotate and resize to catch awkward wrapping or overlaps.
  • Test one real phone like a visitor (menu, scrolling, and one form).
  • Run PageSpeed Insights after major updates (or every few months).
1

Step 1 — Use built-in browser testing tools (free and easy)

➡ What this step does

Most modern browsers include responsive testing tools that let you preview your website on phones, tablets, and desktops.

This is the fastest way to catch layout issues before visitors see them.

📋 What to do
  1. Open your website in Chrome, Edge, or Firefox.
  2. Open Developer Tools, then toggle the device / responsive toolbar.
  3. Switch between phone, tablet, and desktop presets.
  4. Don’t overthink settings: checking a few common sizes catches most problems.
✅ What should happen

You can quickly preview mobile and desktop layouts without changing any site code.

You spot obvious issues like cut-off text, overflow, or broken menus.

2

Step 2 — Test common screen sizes

➡ What this step does

This step confirms your website adjusts correctly to real-world devices.

Test at least: small phone, large phone, tablet, and desktop/laptop.

📋 What to do
  1. Check that text is readable without zooming.
  2. Check that buttons and links are easy to tap (especially on mobile).
  3. Open the navigation menu and click a few pages.
  4. Confirm images stay inside the page and nothing spills off-screen.
  5. Watch for horizontal scrolling (usually a sign something is too wide).
✅ What should happen

Core pages remain readable and usable on mobile and desktop.

Nothing requires pinching, zooming, or side-scrolling to use.

3

Step 3 — Rotate and resize

➡ What this step does

Some layout problems only appear when screens rotate or when the browser window is resized.

Testing both portrait and landscape catches awkward wrapping and overlaps.

📋 What to do
  1. In responsive mode, rotate between portrait and landscape.
  2. Resize the browser window narrower and wider.
  3. Look for headers wrapping awkwardly, buttons overlapping, or forms becoming hard to use.
✅ What should happen

Your layout stays stable when rotated or resized.

Menus, headers, and forms remain usable at common widths.

4

Step 4 — Test on at least one real mobile device

➡ What this step does

Simulators are great for quick checks, but nothing replaces real usage.

Testing one real phone gives you a reliable reality check.

📋 What to do
  1. Open your site on a phone (not just a desktop simulation).
  2. Navigate like a visitor: home, key pages, menu, and contact/donate/adopt actions.
  3. Submit at least one form (if you have one).
  4. Notice load speed, tap accuracy, scrolling comfort, and menu behavior.
✅ What should happen

The site feels natural to use on a phone.

Core actions work everywhere (adopt, donate, contact).

5

Step 5 — Run a quick performance and quality check

➡ What this step does

PageSpeed Insights gives you a fast read on performance and mobile usability.

For rescues: slow sites lose adopters quickly, and mobile performance impacts trust.

📋 What to do
  1. Open PageSpeed Insights.
  2. Paste your website URL and run the audit.
  3. Review Performance, Accessibility, Best Practices, and SEO results.
  4. Re-run after major updates, or every few months. No daily testing needed.
✅ What should happen

You have a short list of improvements to consider (especially for mobile).

You can track whether your site got better or worse after changes.

6

Step 6 — Use AI to speed up reviews (a simple screenshot workflow)

➡ What this step does

AI can help you spot usability issues faster by reviewing screenshots.

Think of AI as a second set of eyes, not the decision maker.

📋 What to do
  1. Take screenshots of your website on mobile and desktop (use responsive mode or a real phone).
  2. Paste the screenshots into your AI tool and use the prompt below.
  3. Apply the top 1-2 improvements first, then re-test quickly.
Copy exactly as shown. Do not modify.
AI helper prompt
Expand to copy: AI review prompt
Copy exactly as shown. Do not modify.
Here are screenshots of my website on mobile and desktop. What looks hard to read, confusing, or difficult to tap?

Please:
- Point out readability issues (text size, spacing, contrast).
- Point out tap/click issues (button size, spacing, menu behavior).
- Point out layout issues (overlaps, cut-off content, horizontal scrolling).
- Suggest 3-5 concrete improvements, prioritized by impact.
✅ What should happen

You quickly identify readability, tap-target, and layout issues.

You get a prioritized list of concrete improvements to try.

What success looks like

  • Visitors don’t need to zoom to read your site
  • Buttons and menus feel natural on mobile
  • Pages load quickly enough to feel “instant” on a phone
  • Core actions (adopt, donate, contact) work across devices

Official References

Open these only if something doesn’t match your screen.

You do not need to read them to complete the guide.

Chrome DevTools: Device Mode Firefox: Responsive Design Mode Safari Developer Tools PageSpeed Insights

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