How to use Site Speed Test Online
- Add a Lighthouse JSON report (or paste it) to Site Speed Test Online to get started.
- Click Read report — Site Speed Test Online processes everything on your device.
- Use the category scores and Core Web Vitals Site Speed Test Online produces — nothing was uploaded.
About this tool
There is no server behind Site Speed Test Online. Site Speed Test Online reads a Lighthouse or PageSpeed Insights JSON report in your browser and surfaces the headline numbers without a server.
It shows category scores and Core Web Vitals such as LCP, CLS and TBT, read straight from the JSON. It behaves the same on desktop and mobile, with nothing stored remotely.
Frequently asked questions
How do I use Site Speed Test Online?
Site Speed Test Online lets you check your input right in the browser, with the result shown instantly and nothing uploaded.
Does Site Speed Test Online cost anything?
No — Site Speed Test Online is completely free, with no sign-up and no hidden limits.
Is my input private in Site Speed Test Online?
Yes — your input never leaves your device; Site Speed Test Online does all the work in your browser.
What file does Site Speed Test Online read?
Export a Lighthouse or PageSpeed Insights JSON report and load it into Site Speed Test Online; it surfaces the scores and Core Web Vitals locally.
Does Site Speed Test Online work on mobile?
Yes — Site Speed Test Online is just a web page and runs on any modern browser, including phones and tablets.