All sites should be protected with HTTPS, even ones that don't handle sensitive data. 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.
Uses HTTP/2 for its own resources
HTTP/2 offers many benefits over HTTP/1.1, including binary headers, multiplexing, and server push. Learn more.
Uses passive listeners to improve scrolling performance
Consider marking your touch and wheel event listeners as passive to improve your page's scroll performance. Learn more.
For users on slow connections, external scripts dynamically injected via document.write() can delay page load by tens of seconds. Learn more.
Links to cross-origin destinations are safe
Add rel="noopener" or rel="noreferrer" to any external links to improve performance and prevent security vulnerabilities. Learn more.
Avoids requesting the geolocation permission on page load
Users are mistrustful of or confused by sites that request their location without context. Consider tying the request to user gestures instead. Learn more.
Page has the HTML doctype
Specifying a doctype prevents the browser from switching to quirks-mode. Read more on the MDN Web Docs page
Some third-party scripts may contain known security vulnerabilities that are easily identified and exploited by attackers. Learn more.
Avoids requesting the notification permission on page load
Users are mistrustful of or confused by sites that request to send notifications without context. Consider tying the request to user gestures instead. Learn more.
Avoids deprecated APIs
Deprecated APIs will eventually be removed from the browser. Learn more.
Allows users to paste into password fields
Preventing password pasting undermines good security policy. Learn more.
No browser errors logged to the console
Errors logged to the console indicate unresolved problems. They can come from network request failures and other browser concerns.
Displays images with correct aspect ratio
Image display dimensions should match natural aspect ratio. Learn more.