Time to First Byte (TTFB)
TTFB measures the time between an HTTP request and the first byte returning from the server — the primary indicator of server-side performance.
Time to First Byte consists of DNS lookup + TCP handshake + TLS handshake + server response time. Under 200ms is excellent, 200–500ms acceptable, above 600ms problematic. TTFB isn't a Core Web Vital but it dictates how fast LCP and FCP can start — a slow TTFB makes other optimisations moot.
Example
A WordPress site on shared hosting has TTFB 1.2s. After migration to a VPS with object caching and Cloudflare, TTFB drops to 180ms — LCP improves automatically by 1 second.
Frequently asked questions
How do I reduce TTFB?
Upgrade server, cache database queries, enable CDN, consider edge computing, HTTP/2 or HTTP/3, fewer redirects, disable slow plugins.
Is TTFB a ranking factor?
Not directly. Indirectly via LCP and UX. Google doesn't call TTFB a ranking signal itself, but fast server = fast LCP = better ranking.
Related terms
Further reading
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