How to use Mobile Website Speed Test
- Add a Lighthouse JSON report (or paste it) to Mobile Website Speed Test to get started.
- Click Read report — Mobile Website Speed Test processes everything on your device.
- Use the category scores and Core Web Vitals Mobile Website Speed Test produces — nothing was uploaded.
About this tool
Everything Mobile Website Speed Test does happens on your own device. Export a report from Chrome DevTools or PageSpeed Insights and load the JSON into Mobile Website Speed Test to see the scores locally.
It shows category scores and Core Web Vitals such as LCP, CLS and TBT, read straight from the JSON. Your input never leaves the page, and no account or install is required.
Frequently asked questions
What does Mobile Website Speed Test do?
Use Mobile Website Speed Test to check your input without installing anything; everything happens client-side.
Is Mobile Website Speed Test free to use?
Yes — Mobile Website Speed Test is completely free, with no usage limits.
Where is my data processed by Mobile Website Speed Test?
Entirely in your browser — Mobile Website Speed Test keeps your data on your own machine and sends nothing anywhere.
What file does Mobile Website Speed Test read?
Export a Lighthouse or PageSpeed Insights JSON report and load it into Mobile Website Speed Test; it surfaces the scores and Core Web Vitals locally.
Can I use Mobile Website Speed Test without a connection?
Yes — after the first load Mobile Website Speed Test runs entirely offline.