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Optimized images load faster and consume less cellular data. Learn more.

Image formats like JPEG 2000, JPEG XR, and WebP often provide better compression than PNG or JPEG, which means faster downloads and less data consumption. Learn more.

Text-based resources should be served with compression (gzip, deflate or brotli) to minimize total network bytes. Learn more.

A long cache lifetime can speed up repeat visits to your page. Learn more.

Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. Learn more

This is the largest contentful element painted within the viewport. Learn More

These DOM elements contribute most to the CLS of the page.

Lists the longest tasks on the main thread, useful for identifying worst contributors to input delay. Learn more

The Critical Request Chains below show you what resources are loaded with a high priority. Consider reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load. Learn more.

To set budgets for the quantity and size of page resources, add a budget.json file. Learn more.

Interactive elements like buttons and links should be large enough (48x48px), and have enough space around them, to be easy enough to tap without overlapping onto other elements. Learn more.

Errors logged to the console indicate unresolved problems. They can come from network request failures and other browser concerns. Learn more

Add `rel="noopener"` or `rel="noreferrer"` to any external links to improve performance and prevent security vulnerabilities. Learn more.

All sites should be protected with HTTPS, even ones that don't handle sensitive data. This includes avoiding mixed content, where some resources are loaded over HTTP despite the initial request being servedover HTTPS. HTTPS prevents intruders from tampering with or passively listening in on the communications between your app and your users, and is a prerequisite for HTTP/2 and many new web platform APIs. Learn more.

Image natural dimensions should be proportional to the display size and the pixel ratio to maximize image clarity. Learn more.

For ideal appearance on iOS when users add a progressive web app to the home screen, define an `apple-touch-icon`. It must point to a non-transparent 192px (or 180px) square PNG. Learn More.

If you've already set up HTTPS, make sure that you redirect all HTTP traffic to HTTPS in order to enable secure web features for all your users. Learn more.

If the width of your app's content doesn't match the width of the viewport, your app might not be optimized for mobile screens. Learn more. The viewport size of 362px does not match the window size of 360px.

A maskable icon ensures that the image fills the entire shape without being letterboxed when installing the app on a device. Learn more. No manifest was fetched

The browser address bar can be themed to match your site. Learn more. Failures: No manifest was fetched, No `<meta name="theme-color">` tag found.

A themed splash screen ensures a high-quality experience when users launch your app from their homescreens. Learn more. Failures: No manifest was fetched.

A service worker enables your web app to be reliable in unpredictable network conditions. Learn more. No usable web app manifest found on page.

If you're building a Progressive Web App, consider using a service worker so that your app can work offline. Learn more.

All sites should be protected with HTTPS, even ones that don't handle sensitive data. This includes avoiding mixed content, where some resources are loaded over HTTP despite the initial request being servedover HTTPS. HTTPS prevents intruders from tampering with or passively listening in on the communications between your app and your users, and is a prerequisite for HTTP/2 and many new web platform APIs. Learn more.

Browsers can proactively prompt users to add your app to their homescreen, which can lead to higher engagement. Learn more. Failures: No manifest was fetched.

The service worker is the technology that enables your app to use many Progressive Web App features, such as offline, add to homescreen, and push notifications. Learn more.

Link text (and alternate text for images, when used as links) that is discernible, unique, and focusable improves the navigation experience for screen reader users. Learn more.

Screen readers have a specific way of announcing lists. Ensuring proper list structure aids screen reader output. Learn more.