Measures the server's response time to the first byte.
TTFB measures how long it takes for a browser to receive the first byte of data from your server after making a request. It's a measure of server responsiveness.
A fast TTFB is a sign of a healthy and well-optimized server. A slow TTFB means users are waiting longer for anything to even start appearing on their screen.
A high TTFB directly leads to slower page load times and a poor user experience. Google considers it an important metric for page experience.
Run a free audit to see how your site performs on Time To First Byte (TTFB) 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.