Server Response Time Explained: Measuring and Improving Server Response Time

Fast loading times are a crucial factor for the success of a website, and server response time forms the foundation of this. A slow server response can deter visitors and undermine SEO efforts. In this article, we explain why server response time is so important, how it is measured, and how it can be improved.

What is Server Response Time (SRT)?

Server Response Time (SRT), also known as server response time in German, is the period a server takes to respond to a client's request. It starts when the client sends the request and ends when the first data byte from the server reaches the client. This time includes the duration for transmitting the request to the server, processing the request by the server, and the start of transmitting the response back.

Server Response Time is not about the pagespeed of a website. Instead, it precisely refers to the duration it takes for a client to receive the first "sign of life" from a server after making a request. The server response time is therefore highly dependent on the server's performance (and its geographical distance from a visitor). The faster it processes and responds to information, the shorter the response time, and the earlier the transfer of requested data can begin.

Distinguishing Between Server Response Time and Server Speed

Server response time and server speed are two distinct yet interconnected concepts.

Server Response Time

• This is the time taken for the server to send the initial response to a request.
• It includes the network transfer time of the request, processing time on the server, and the time taken to send the first byte back to the client.
• Server response time is heavily influenced by the server's performance, network infrastructure, and the distance between the server and client.

Therefore, server response time is closest to the performance metric TTFB (Time to First Byte).

Server Speed

• This is the total time required to fully load a webpage in the user's browser.
• It starts with sending the request to the server and ends when all resources of the page (HTML, CSS, JavaScript, images, etc.) are fully loaded and rendered.
• Server speed depends not only on server response time but also on the size and number of resources, efficiency of client-side scripts, network speed, and other factors such as caching and Content Delivery Networks (CDNs).

Therefore, server speed is closest to the performance metric LCP (Largest Contentful Paint).

While server response time represents an early, specific part of the loading process, server speed encompasses the entire process until the page is fully displayed in the browser. Both are important metrics for web performance optimisation, but they address different aspects of loading times.

How to measure Server Response Time?

There are numerous tools available for measuring a server's response time, some of which can also be used online. One of the oldest tools, and certainly the most well-known, is the ping command, which has been included in all operating systems since MS-DOS in the 1980s and remains a basic tool in Microsoft Windows or Linux. It has been used for decades to measure and improve networks and is still in use today.

Using a server monitoring tool allows you to regularly capture and measure response time.

Furthermore, there are now many other tools available, some of which can be operated online in a browser. These tools offer several advantages that make measuring and improving response time much easier compared to earlier times. One crucial advantage in the age of global connectivity is the ability to measure server response time from different locations around the world. Roughly speaking, a data packet transmitted at the speed of light in a fibre optic cable from Europe to Australia takes at least 100 ms. Unofficially, a fast server response time is considered to be around 200 ms. This includes delays caused by processing information in multiple routers and the receiving computer.

Some examples of popular and reliable platforms for measuring response time include GTmetrix or Pingdom.

Graphic: Measuring Server Response Time with GTmetrix

What factors can improve the Server Response Time?

The server response time is influenced by a variety of factors, both technical and infrastructural:

Server Location and Geography

The physical location of the server can significantly affect response time. The further the server is from the user's location, the longer the data transfer takes. Therefore, geographically distributed servers or Content Delivery Networks (CDNs) can reduce response times by using servers located closer to users. Therefore, hosting in Germany is recommended for websites targeting domestic visitors.

Server Performance and Hardware

The server's hardware, including processor performance, memory, and disk speed, directly impacts request processing time. More powerful servers can process requests faster, leading to shorter response times. Additionally, using Solid-State Drives (SSDs) instead of traditional hard drives can improve performance.

Web Hosting Type

The type of web hosting plays a significant role:

• Shared Web Hosting: Multiple websites share the same server and its resources. This can lead to overloads and longer response times.
• VPS Hosting: Provides dedicated resources within a shared server, resulting in better response times compared to Shared Hosting.
• Dedicated Server: All server resources are dedicated to a single website, enabling optimal performance.
• Cloud Server: Utilises a network of virtual servers to respond flexibly to peak loads and ensure stable response times.

Tip: Learn about measuring, comparing, and optimizing CPU performance on VPS hosting and measuring, comparing, and optimizing disk performance on VPS hosting

Network Conditions and Bandwidth

The network connection between the server and users affects response time. Higher bandwidths and stable networks can reduce the transmission time of requests and responses. Network failures or bottlenecks, on the other hand, can lead to delays.

Application Code and Database Optimization

The website's source code and database configuration can significantly impact server response time. Inefficient code, unnecessary database queries, or unoptimized database tables can prolong processing time. Performance can be greatly improved through code optimizations, database indexing, and caching mechanisms.

Content Delivery Networks (CDNs)

Content Delivery Networks (CDNs) store copies of website content on servers distributed worldwide. By retrieving content from a geographically closer server, response times can be significantly reduced. This is particularly useful for global websites with users from different regions.

Caching Strategies

By caching frequently requested data at various levels (browser cache, server cache, proxy cache), the need to process the same requests multiple times can be reduced. This leads to faster response times as cached content can be delivered more quickly.

Minimizing HTTP Requests and Resource Optimization

The number and size of resources that need to be provided by the server affect response time. By minimizing HTTP requests, compressing files (e.g. images, scripts, stylesheets), and utilising modern web technologies like HTTP/2, overall loading times can be improved.

These factors together determine the efficiency and speed at which a server responds to requests and should be carefully monitored and optimised to ensure an optimal user experience.

A fast server response time is essential for optimising user experience, increasing conversion rates, and improving search engine rankings. By taking targeted actions such as optimising server location, hardware, code, and caching strategies, server response time can be effectively reduced. Overall, optimised server performance leads to happier users and better visibility on the web.

Our article is based on our own experiences and research, as well as information from external sources.

Article last updated:
Update 12.06.24: Content updated and expanded.

Sources & further links on the topic:
https://tool.pingdom.com/ (Tool for measuring Server Response Time)
https://gtmetrix.com/ (Tool for measuring Server Response Time)

Image credit:
Anton Makarenko on pexels.com