TTFB
Time to First Byte (TTFB) measures how long it takes for the browser to receive the first byte from the server after a request. It captures how fast the server itself responds — the starting point for every other speed metric (LCP, FCP, page load).
Time to First Byte (TTFB) measures how long it takes for the browser to receive the first byte from the server after a request. It captures how fast the server itself responds — the starting point for every other speed metric (LCP, FCP, page load).
Why It Matters
TTFB isn't one of the official Core Web Vitals, but LCP can't be good unless TTFB is good first. Web.dev's recommended 2026 threshold is ≤ 800ms; anything above 1.8s produces measurable bounce and ranking loss. Cloudflare analysis reports ~12% conversion lift on sites that cut TTFB by 500ms. TTFB is easy to measure, responds instantly to CDN, hosting, and server optimizations, and sits high on any technical SEO priority list.
Components
TTFB is the sum of several network and server stages:
- DNS lookup: Resolving the domain to an IP
- TCP connection: Three-way handshake
- TLS negotiation: HTTPS encryption handshake
- Request send: Request traveling to the server
- Server processing: Application generating the response (DB queries, rendering)
- First byte received: First byte landing at the browser
A slowdown in any stage adds to TTFB.
Thresholds
| Rating | TTFB |
|---|---|
| Good | ≤ 800ms |
| Needs Improvement | 800ms–1.8s |
| Poor | > 1.8s |
Scored at the 75th percentile (p75) of real-user data from the Chrome User Experience Report.
How to Improve
Use a CDN: Edge servers handle DNS, TCP, TLS, and request forwarding closer to the user — the single biggest win.
Enable HTTP/2 and HTTP/3: Connection reuse and multiplexing cut handshake costs. Usually on by default in Cloudflare, Fastly, and similar CDNs.
Server-side caching: Cache dynamic pages in Redis or Varnish to strip hundreds of milliseconds from server processing.
Optimize DB queries: Slow queries, missing indexes, and N+1 problems dominate Server Processing time.
Static Site Generation (SSG): Frameworks like Next.js and Astro prebuild pages to HTML, so the server just returns a static file. TTFB drops dramatically.
Pick the right server region: Host near your main user base.
Minimize cookies and headers: Bloated cookies and tracking headers inflate request/response sizes.
Remove redirect chains: Every redirect adds to TTFB. Keep redirects direct.
Measurement Tools
- Chrome DevTools → Network → Timing: Per-request TTFB breakdown
- WebPageTest: TTFB by region and device
- PageSpeed Insights: CrUX-based field data
- Search Console → Core Web Vitals: Real-user TTFB trends
Sources: