Google retired its own Mobile-Friendly Test in December 2023, yet people still search for it every month. The Kwebby Mobile Friendly Test fills part of that gap: it runs any URL through the Google PageSpeed Insights API on a simulated phone and returns four Lighthouse scores, a viewport check and lab metrics for loading and layout stability.
This page explains what that test covers, what Google offers today, and how to make a site work well on phones.
Key Takeaways
- Google retired its Mobile-Friendly Test, the Mobile Usability report and the API in December 2023, and the old test address now redirects to Lighthouse documentation.
- Kwebby's Mobile Friendly Test uses the Google PageSpeed Insights API to return mobile scores for performance, accessibility, best practices and SEO, a viewport check, and lab values for FCP, LCP, CLS and TBT.
- Google indexes the mobile version of your site, so content missing on mobile can drop out of the index.
- Core Web Vitals are used by Google's ranking systems, with good values of LCP up to 2.5 seconds, INP up to 200 milliseconds and CLS up to 0.1.
- Tap targets should measure at least 48 by 48 pixels with about 8 pixels of space between them.
- Test on a real phone after every fix, because a score is only a proxy for what visitors feel.
What Is the Kwebby Mobile Friendly Test?
Kwebby's Mobile Friendly Test is a free web tool that tests a URL for mobile performance. It sends the page to the Google PageSpeed Insights API with the mobile strategy and returns four Lighthouse category scores, a viewport check and four lab metrics. It tests mobile only; for desktop results use the Page Speed Checker. No account is needed, and each visitor can run 10 tests a minute.
It is not Google's old Mobile-Friendly Test, which no longer exists, and it does not give a pass or fail verdict.
What Happened to Google's Mobile-Friendly Test?
Google retired the standalone Mobile-Friendly Test in December 2023. A notice on Google's Search Central blog reads: "As of December 2023, the Mobile Friendly Test has been retired."
The Mobile Usability report in Search Console and the Mobile-Friendly Test API went with it. The old test address, search.google.com/test/mobile-friendly, now redirects to the Lighthouse overview. Lighthouse is an open-source tool with audits for performance, accessibility, SEO and more. You can run it in Chrome DevTools, from the command line, as a Node module or through PageSpeed Insights.
Key Features and How It Works
The test is one form with one button. Behind it sits PageSpeed Insights, the same engine that powers Kwebby's Page Speed Checker.
Four Lighthouse Scores
The tool returns mobile scores for Performance, Accessibility, Best Practices and SEO, each from 0 to 100. PageSpeed Insights colors scores in three bands: 90 to 100 is good, 50 to 89 needs improvement and 0 to 49 is poor. Mobile scores usually sit below desktop scores because the lab test simulates a mid-tier phone on a mobile network.
Lab Metrics
The tool shows four lab values from the simulated phone: First Contentful Paint (FCP), Largest Contentful Paint (LCP), Cumulative Layout Shift (CLS) and Total Blocking Time (TBT). Lab tests cannot measure INP, because INP needs real user input, so TBT serves as the lab signal for responsiveness. The tool does not show real-user field data.
Core Web Vitals measure loading, responsiveness and visual stability. According to PageSpeed Insights documentation, a page passes when the 75th percentile of real-user values for all three metrics is good:
- LCP (Largest Contentful Paint): good is 2,500 milliseconds or less.
- INP (Interaction to Next Paint): good is 200 milliseconds or less.
- CLS (Cumulative Layout Shift): good is 0.1 or less.
Viewport Check
The report shows whether the page has a viewport meta tag, which mobile browsers need to size the page to the screen. It also shows the Lighthouse version that ran the test. For a full list of fixes, open the same URL in PageSpeed Insights or Chrome DevTools.
Why Mobile Friendliness Matters
Mobile friendliness matters because Google builds its index from the mobile version of your site. Google's mobile-first indexing guide tells site owners to serve the same content on mobile and desktop. If the mobile page has less content, you lose traffic for what is missing.
Mobile usability is no longer a separate ranking signal that you pass or fail. Google's page experience documentation says there is no single signal, and that Core Web Vitals are used by its ranking systems. Visitors still bounce from pages that load slowly or need pinching and zooming, which costs you leads whatever the ranking effect is.
Phones are where many visits happen. Shopify's 2026 guide, citing Statista, reports that smartphones made up roughly three quarters of US retail website visits in the first quarter of 2026 (source).
How to Use the Mobile Friendly Test
Follow these steps to test one page.
- Enter the URL. Type the full address of the page, for example https://example.com, in the URL box.
- Press Test. The tool sends the page to PageSpeed Insights and waits for the result.
- Read the four scores. Compare each with the bands: 90 to 100 good, 50 to 89 needs improvement, 0 to 49 poor.
- Check the lab metrics and viewport. Compare LCP and CLS with the good values listed above, and fix a missing viewport tag first.
- Fix the largest problems. Start with heavy images and blocking scripts, which usually move LCP and TBT the most.
- Test again. Re-run the same URL after each change to confirm the score moved.
- Confirm on a real phone. Open the page on a phone and use the device toolbar in Chrome DevTools to check layouts at several widths.
Best Practices for Mobile-Friendly Pages
A mobile-friendly page has a correct viewport, readable text, usable tap targets and no sideways scrolling. These checks catch most problems before a score does.
Set the Viewport Meta Tag
Add <meta name="viewport" content="width=device-width, initial-scale=1"> to the head. Without it, mobile browsers render the page at desktop width and shrink it. Common mistake: setting a fixed pixel width in the viewport tag.
Keep Text Readable Without Zooming
Use a base font size of at least 16 pixels for body text, a common starting point. Check that line length and contrast still work on a narrow screen.
Size Tap Targets for Thumbs
Web.dev recommends touch targets of at least 48 by 48 pixels with about 8 pixels of spacing. Crowded links in a footer or menu are a frequent failure.
Avoid Horizontal Scrolling
Use relative widths, such as percentages, instead of fixed pixel widths. Wide tables, images and embedded code are the usual cause.
Serve the Same Content on Mobile
Show the same text, images and structured data on both versions of the page. Hidden or trimmed mobile content can disappear from the index.
Cut Page Weight
Phones on slow connections feel every extra kilobyte. Measure total weight with the Page Size Checker and confirm text compression with the Gzip Compression Checker.
Common Use Cases
- Pre-launch checks. Test the main templates (home page, article, product) before a release.
- After a redesign. Compare mobile scores before and after the new theme.
- Client reports. Agencies attach the mobile scores and lab metrics to a monthly report.
- Competitor benchmarks. Test a rival's page to see where your mobile score stands.
- Broader audits. Pair the test with the Website Reviewer for a wider look at SEO health.
Related Kwebby Tools
These tools cover the checks around mobile testing. See the full SEO Tools group for more.
- Page Speed Checker shows desktop and mobile results from PageSpeed Insights, with Core Web Vitals.
- Page Size Checker measures the HTML size of a page and counts CSS, JavaScript and image files.
- Check Gzip Compression verifies that your server compresses text files.
- Website Reviewer gives a wider review of a site beyond the mobile view.
Frequently Asked Questions (FAQs)
Does Google still have a Mobile-Friendly Test?
No. Google retired the Mobile-Friendly Test, the Mobile Usability report and the API in December 2023. The old test address now redirects to Lighthouse documentation, and Google directs site owners to Lighthouse.
What is a mobile-friendly test?
A mobile-friendly test checks how well a page works on a phone. It looks at layout, text size, tap targets and speed. Kwebby's version uses PageSpeed Insights to return mobile Lighthouse scores, a viewport check and lab metrics.
How do I make my website mobile-friendly?
Use responsive design with a correct viewport tag, readable text and tap targets of at least 48 by 48 pixels. Avoid horizontal scrolling and serve the same content on mobile as on desktop. Then reduce page weight so the page loads fast on a mobile network.
What is mobile-first indexing?
Mobile-first indexing means Google uses the mobile version of your site for indexing. If the mobile page has less content than the desktop page, that content may not be indexed.
Does mobile-friendliness affect SEO?
Indirectly, yes. Google indexes the mobile version and uses Core Web Vitals in its ranking systems. Google also says there is no single page experience signal, so relevance still comes first.
Is the Kwebby Mobile Friendly Test free?
Yes. The test is free to use and needs no account. Each visitor can run up to 10 tests a minute.
Final Thoughts
A mobile test works best as a routine. Run it on your key pages, fix the biggest items and re-run it after every release. Treat the score as a guide and confirm the result on a real phone.
Put mobile checks inside a full process with the Technical SEO Checklist. If your site needs a rebuild to work well on phones, Kwebby's web development services cover redesigns.