Time to First Byte (TTFB)

Time to First Byte (TTFB)Time to First Byte (TTFB) is the time until the browser receives the first byte of the server response, describing how quickly the server reacts.Open glossary entry → measures the time from requesting a page to the arrival of the first byte of the server response. TTFB is not a Core Web Vital itself, but it strongly influences Largest Contentful Paint (LCP)Largest Contentful Paint (LCP) measures when the largest visible content element in the viewport has loaded, representing the perceived loading speed.Open glossary entry →: if the server responds slowly, no front-end optimisation can fully rescue the LCP.

A high TTFB often points to slow hosting, missing cachingCaching stores previously retrieved content so it is available faster on repeat requests, relieving both servers and the network.Open glossary entry → or unoptimised database queries. Measures to improve it include:

• good hosting plus page, object and edge caching,
• database optimisation and server-side caching in the CMSA content management system (CMS) is software for creating, managing and publishing web content, usually without programming knowledge. Well-known examples are WordPress or Shopify.Open glossary entry →,
• a content delivery network (CDN)A content delivery network (CDN) is a network of distributed servers that delivers static content closer to the user, reducing loading times.Open glossary entry → for static content,
• modern protocols such as HTTPHTTP (Hypertext Transfer Protocol) is the protocol through which browsers and servers exchange web content. HTTPS is the encrypted, secure variant of this protocol.Open glossary entry →/2 or HTTP/3 and compression,
• avoiding unnecessary redirectsA redirect forwards users and search engines from one URL to another. It can be permanent (301) or temporary (302) and transfers signals to the target URL.Open glossary entry →.

TTFB becomes visible in tools such as WebPageTest or the Chrome DevTools waterfall analysis.