Glossary
TTFB (Time To First Byte)
TTFB measures how long after a request the first byte of the response arrives, reflecting server, network, and backend processing speed.
TTFB (Time To First Byte) measures the delay between a browser sending a request and receiving the first byte of the response. It is a key indicator of how responsive the server and network are.
What it includes
- DNS resolution, TCP, and
ssl-tlshandshake time. - Network round-trip latency to the server.
- Server processing — running
php, queryingmysql, and assembling the page.
How to improve it
- Caching — serve precomputed pages so the backend does less work.
- A
cdn— answer from an edge near the visitor. - Faster backend code, tuned databases, and
http-2/http-3.
Why it matters for hosting
TTFB heavily influences perceived speed and contributes to core-web-vitals. A high TTFB usually points to slow server-side processing or distant hosting — both directly tied to your host's performance and location.
See also
Core Web Vitals
Core Web Vitals are Google’s user-experience metrics — LCP, INP, and CLS — that measure loading, interactivity, and visual stability of a page.
Caching
Caching stores copies of data or pages so repeat requests are served instantly, reducing server work and dramatically speeding up websites.
CDN (Content Delivery Network)
A CDN is a worldwide network of edge servers that cache and serve your site close to visitors, cutting latency and absorbing traffic spikes.
PHP
PHP is a widely used server-side scripting language that powers WordPress and much of the web, generating dynamic pages on the server.