TTFB

What Is TTFB?

A high TTFB value not only slows down the perceived load time but also degrades all downstream performance metrics like LCP and CLS. The cause is often poorly configured hosting, missing caching strategies, or overloaded databases. The good news: TTFB optimization is one of the technical SEO measures with the best effort-to-benefit ratio.

TTFB (Time to First Byte) is the time span between requesting a page and the first data byte arriving from the server. This metric measures server performance and responsiveness — not overall page load speed, but just the connection and server response time. A low TTFB value (under 200ms is good) indicates a fast, well-configured server.

Technically, TTFB encompasses several aspects: DNS resolution (how long it takes to convert the domain name into an IP address), TCP connection (establishing the connection), TLS handshake (for HTTPS), and server processing (database queries, PHP execution, etc.). A high TTFB (over 600ms) indicates server issues, database bottlenecks, or geographically unfavorable hosting locations. CDNs reduce TTFB through geographically distributed servers.

In practice, check TTFB regularly with Google PageSpeed Insights or WebPageTest. A poorly configured or overloaded web server significantly increases TTFB. Optimizations include: switching to a faster hosting provider, optimizing database queries, implementing caching, or using a CDN. TTFB is often underestimated — a high TTFB also drives other performance metrics (LCP, CLS) upward because the browser has to wait longer for data.