TL;DR TTFB
TTFB stands for Time to First Byte and it measures the time that elapses between a browser sending a request for a web page and receiving the very first byte of the response from the server. It is one of the earliest and most fundamental indicators of web server performance. A high TTFB means something is slow before the browser has even started downloading the page, whether that is a slow server, an overloaded database, unoptimised PHP, or long network travel times. A low TTFB means the server responded quickly and the browser can start rendering the page sooner. Google measures TTFB as part of its Core Web Vitals assessment through the Largest Contentful Paint metric, so it has a direct impact on your search rankings. CloudSonic's stack is tuned specifically to minimise TTFB through Nginx, Redis object caching, NVMe storage, and edge caching working together.
How TTFB Is Measured
TTFB is measured from the moment a browser sends an HTTP request to the moment it receives the first byte of the HTTP response. This time period encompasses several distinct phases. First is the DNS lookup time, the time taken to resolve the domain name to an IP address. Second is the connection time, the time taken to establish a TCP connection and complete the TLS handshake for HTTPS connections. Third is the server processing time, the time the server spends actually generating the response, which for a WordPress page includes bootstrapping PHP, querying the database, and rendering the template. The first byte arrives when the server has finished processing and begins streaming the response. Of these three phases, server processing time is typically the largest and the most directly influenced by hosting infrastructure quality. DNS lookup time is improved by using a fast DNS provider like Cloudflare, and connection time is improved by HTTP/3 and TLS 1.3 which reduce handshake round trips.
# Measure TTFB and all connection phases with curl
curl -o /dev/null -s -w "\
DNS lookup: %{time_namelookup}s\n\
TCP connect: %{time_connect}s\n\
TLS handshake: %{time_appconnect}s\n\
Time to first byte:%{time_starttransfer}s\n\
Total time: %{time_total}s\n" \
https://cloudsonic.com.au
# Output example:
# DNS lookup: 0.012s
# TCP connect: 0.031s
# TLS handshake: 0.078s
# Time to first byte: 0.091s
# Total time: 0.143s
Why TTFB Matters for Your Website
TTFB is the starting gun for everything else that happens in a page load. No rendering, no asset loading, no interactivity can begin until the browser receives that first byte. A high TTFB delays everything downstream regardless of how optimised the rest of the page is. You can have perfectly compressed images, efficient JavaScript, and a lean stylesheet, but if the server takes two seconds to respond, the visitor stares at a blank page for two seconds before any of those optimisations can take effect. Google measures TTFB as a component of Largest Contentful Paint, the primary Core Web Vitals metric, which means a high TTFB directly penalises your search rankings. A good TTFB is under 200 milliseconds at the server level before network transit is added. Achieving this requires fast server hardware, efficient application code, effective caching with Redis, and delivery through a CDN with edge caching to minimise the distance between the server and the visitor.
