TTFB (Time To First Byte)
TTFB measures request-to-first-byte latency. Good ≤800ms. Driven by CDN edge distance, origin response, TLS handshake, SSR render time — the upstream bottleneck for other Core Web Vitals.
Category: Metrics
What is TTFB (Time To First Byte)?
TTFB measures request-to-first-byte latency. Good ≤800ms. Driven by CDN edge distance, origin response, TLS handshake, SSR render time — the upstream bottleneck for other Core Web Vitals.
How do you apply it in practice?
Wins: edge-cache HTML, HTTP/3, TLS 1.3 0-RTT, slim SSR.
Why does it matter for AI search citations?
Generative search engines tend to extract sentences that are clearly defined, consistent and quotable on their own. Writing concepts like "TTFB (Time To First Byte)" as one consistent definition across your site, backed by structured data and verifiable sources, lowers the chance of being misread. This improves readiness only; it does not guarantee citations or ranking gains — measure actual citations to know.
Which related terms should you know?
Core Web Vitals
Core Web Vitals are Google's three UX performance metrics: LCP (Largest Contentful Paint ≤2.5s), INP (Interaction to Next Paint — Good ≤200ms / Needs Improvement 200-500ms / Poor >500ms), CLS (Cumulative Layout Shift ≤0.1). All three must be green to qualify as 'Good' and affect mobile ranking.
Page Speed
Page Speed measures the time from request to interactive, quantified by the three Core Web Vitals (LCP / INP / CLS). Mobile thresholds are stricter — on 3G, LCP should be ≤4s; each extra second adds ~7% to bounce rate.
TTFB (Time To First Byte) at a glance
| Term | TTFB (Time To First Byte) |
|---|---|
| Category | Metrics |
| Last reviewed | 2026-10-06 |
References
- Google Search Central: SEO documentation
- Schema.org structured data vocabulary
- W3C JSON-LD 1.1 Recommendation
- GEO: Generative Engine Optimization (arXiv paper)
These documents support the definitions and methods, not ranking or citation promises; reviewed as of 2026-10-06.
By the 23SEOGEO team · Last updated: