Checks Cache-Control headers, ETag, and Last-Modified for proper caching configuration.
This check examines how your server tells browsers and CDNs to cache (temporarily store) your website's files. It looks at Cache-Control headers (which specify how long files should be stored and whether they can be shared), ETag headers (which help browsers check if a file has changed since last visit), and Last-Modified headers (which tell browsers when a file was last updated).
When a visitor returns to your site or navigates to another page, proper caching means their browser can reuse files it already downloaded instead of fetching them again from your server. This makes repeat visits dramatically faster, reduces your server load and hosting costs, and saves bandwidth — especially important for mobile users on limited data plans.
Poor caching configuration forces browsers to re-download the same files on every visit, resulting in noticeably slower page loads, higher server costs, and a worse user experience. Properly configured caching can make your site feel nearly instant for returning visitors.
Run a free audit to see how your site performs on Cache Configuration and 159 other checks.
Start Free AuditChecks if images use responsive techniques like srcset.
Checks if images have width and height attributes to prevent layout shift.
Checks for JavaScript errors in the browser console. (Note: In-dev check)
Measures the total size of the HTML document.