Server Response Time.
Learn what Server Response Time means in modern search and SEO.
The time a web server takes to respond to a browser's initial request — also known as Time to First Byte (TTFB) — a foundational factor in page speed and Core Web Vitals.
Server response time is the time elapsed from when a browser sends an HTTP request to when it receives the first byte of the server's response. It is equivalent to Time to First Byte (TTFB). A slow server response time delays the start of everything else — downloading HTML, parsing content, fetching sub-resources. Google considers a TTFB under 200ms good; above 600ms is poor. Server response time is measured separately from overall page load time because it isolates infrastructure performance from front-end optimisation.
Causes of Slow Server Response Time
Unoptimised database queries are the most common cause — pages that execute dozens of database calls before serving HTML will always be slow. Other causes include: insufficient server hardware or shared hosting limitations; missing server-side caching (every request regenerates dynamic content from scratch); unoptimised server-side code; slow third-party API dependencies in the request path; and geographic distance between the server and the user (mitigated by CDN edge nodes).
Improving Server Response Time
Key improvements include: implementing server-side page caching (Redis, Memcached, Varnish, or plugin-level caching for WordPress); optimising database queries and adding indexes; upgrading server specifications or moving to a dedicated server; using a CDN to serve static content from geographically distributed edge nodes; and minimising synchronous third-party calls in the request-response cycle. For managed hosting, switching from shared to VPS or dedicated hosting often produces immediate TTFB improvements.
Related Terms
Articles about Server Response Time
Read more on the Aergos blog.
The Complete Technical SEO Handbook: August 2025 Edition
This is the technical SEO reference you bookmark and come back to. Updated for August 2025, this guide covers every foundational and advanced technical discipline — from crawl budget to JavaScript rendering to log file analysis — with the depth that actually moves rankings.
Read article
Best AI Visibility Checkers: Free and Paid Ways to See If AI Mentions You
Not sure if AI search engines are mentioning your brand? This guide breaks down the best free and paid AI visibility checker tools — from instant one-time audits to continuous monitoring — so you know exactly where you stand.
Read article
Core Web Vitals in 2025: What Actually Affects Your Rankings
Core Web Vitals aren't going away — but a lot of what gets written about them is either outdated or overcomplicated. Here's what Google actually weighs in 2025, explained in plain English, with real fixes you can action today.
Read article
Best AEO Tools: Answer Engine Optimization Software Compared (2025)
Answer engine optimization is no longer optional. These AEO tools help you track AI citations, research question-based queries, and show up when ChatGPT, Perplexity, and Google AI Overviews answer your customers' questions.
Read article
How Long Does SEO Take? Setting Honest Expectations
SEO timelines vary wildly depending on your site's age, competition, and technical health. Here's an honest breakdown of what to expect and when — no hype, no vague promises.
Read article
What 100 Client-Submitted AI Audits Taught Us About LLM SEO Tools
Clients started showing up with AI-generated SEO audits. After reviewing more than a hundred of them, clear patterns emerged — and most of them weren't good. Here's what these tools consistently get wrong, and what a real audit actually needs.
Read articleReady to close the loop?
See every term in action
Aergos tracks your AI and organic visibility across every channel, in one platform.
Not ready to talk? Audit your site free →