Upload a HAR file and view requests in a waterfall chart, resource sizes, HTTP headers, and response bodies.

See whether your website requires JavaScript to load, and how JS code impacts your Largest Contentful Paint metric and total page weight.

This tool analyzes the loading speed of your website and provides detailed reports that help you optimize it. View how your site renders frame by frame and use identify network requests that slow down your site.

This tool parses HTML code to identify what causes bloated document responses. For example, you might find that there are large inline images or that there's a big chunk of JSON for hydrating a single-page app.

This tool analyses CSS code to identify large rules and selectors. You might find that there are large CSS selectors generated by Sass or assets like images or fonts embedded in the file.

Resource hints like preload and preconnect can make sites load faster, but can also hurt performance if used wrongly. This tool checks your site for common problems with them.