How to use Website Performance Checker
- Add a Lighthouse JSON report (or paste it) to Website Performance Checker to get started.
- Press Read report to run it locally in your browser.
- Review the category scores and Core Web Vitals shown below.
About this tool
Website Performance Checker is a static, client-side tool with no backend. Export a report from Chrome DevTools or PageSpeed Insights and load the JSON into Website Performance Checker to see the scores locally.
Because Website Performance Checker parses a report you provide, the results match whatever run you exported. Nothing you enter is uploaded, and it keeps working offline once the page has loaded.
Frequently asked questions
What is Website Performance Checker for?
Website Performance Checker runs entirely on your device: add your input, and it checks it locally in real time.
Is Website Performance Checker free to use?
Yes — Website Performance Checker is completely free, with no usage limits.
Where is my data processed by Website Performance Checker?
Entirely in your browser — Website Performance Checker keeps your data on your own machine and sends nothing anywhere.
What file does Website Performance Checker read?
Export a Lighthouse or PageSpeed Insights JSON report and load it into Website Performance Checker; it surfaces the scores and Core Web Vitals locally.
Does Website Performance Checker work on mobile?
Yes — Website Performance Checker is just a web page and runs on any modern browser, including phones and tablets.