Overview
TTFB is a foundational metric for measuring server responsiveness. It includes the time for DNS lookup, TCP connection, TLS handshake, and the time the server takes to process the request and generate the response.
Factors Affecting TTFB
- Server load and performance.
- Database query speed.
- Network latency.
- CDN configuration.
- Server-side processing complexity.
Importance
While not a Core Web Vital, a high TTFB makes it impossible to achieve good scores for other loading metrics like FCP and LCP.