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Response Time


What Is Response Time?

Response time refers to the amount of time it takes for a server to respond to a client’s request. Measured in milliseconds, the timer starts from the moment a client sends out a request and stops when the server sends back its first response.

Response time is sometimes defined as Time to First Byte (TTFB), which is the amount of elapsed time from the client request until the first packet of data is sent back to the client. Response time does not include the amount of time it takes for the client’s device to render or process any of the received data. 

Response time is the sum of five parts:

  1. DNS Lookup Time  
  2. Authentication and connection time
  3. Redirect Time 
  4. Time to First Byte
  5. Time to Last byte

DNS Lookup time is the amount of time it takes for a computer to send a request to a domain name server and receive the requested domain’s IP address. A good DNS lookup time ranges between 20 – 120 milliseconds. 

Authentication and connection time refers to the time it takes a computer to establish a secure and encrypted connection with the webserver before transmitting the requested data packets. This is accomplished by completing a TCP (and/or TLS) three-way security handshake. On average, establishing these secure connections through SSL can take from 250 milliseconds to half a second, sometimes even longer. Network latency can greatly influence the connection time.

Redirect time is the time required for a server to request any additional DNS data and perform any necessary redirects to another server with more recent information. On average, the redirect time should be between 0 – 300 milliseconds.

Time to First Byte is the time it takes for the first bits of real application data to be transferred between client and server. While switching from the handshake protocol, the record protocol allows for the transmission of actual data packets relating to the website or application. To not affect your users’ experience, the first byte should score between 0 – 200 milliseconds.

Time to Last byte Is the time between the moment the request is sent by the client and the moment when the last byte of data was received in response.

Why Does Response Time Matter?

Web page response time is an important metric to track and monitor as it gives you insight into server performance. If your server’s response time is high, it may indicate that your server is overloaded and having difficulties processing requests.

Google considers response time a ranking factor for both desktop and mobile searches. When your website or application continually generates long response times, search engines will rank it lower on the search engine results page (SERP). This has the potential to harm your website’s traffic and growth.

High website response times also create an unpleasant user experience (UX). Web developers have known for a long time that if your page takes too long to load, users will likely leave your site, which will make your business suffer.

Response Time vs. Page Load Time

Response time refers to the speed at which the server can respond to a request.

Page load time is the time it takes for a page to load completely.

Page load time will be generally very much impacted by the server response time as for every request that the webpage makes, the server will have to respond with a message. A slow response time will increase the page load time while a fast response will decrease it.

It’s worth noting that both these metrics can tell you a lot about the performance of your page and should be measured and monitored constantly.

Read the article on page load time to learn more about it.

Standards: What Is a Good Response Time

According to Google, the average response time should be under 200 milliseconds as it gives the feeling of an instant response. 

A web response time ranging between 200 milliseconds and 1 second is considered acceptable as users still likely won’t notice the delay. For better user satisfaction, you should take the time to optimize it. 

Any response time over 1 second is problematic and needs to be fixed. The higher the response, the higher the chances of users leaving your website or application. 

How to Check Response Time

To check a website response time you’d likely need to use a website monitoring tool. Once you start measuring and monitoring the response time, you’ll want to pay close attention to these 3 metrics as they will help you paint a clear picture of how your website is performing: 

  • Average response times, which is just an average of the time taken for every round trip request.
  • Peak response time, which is what you would use to find problematic requests.
  • Error rates, which refer to the percentage of failed requests. 

How to Reduce Server Response Time

Here are some tips to create, improve, and maintain a fast response time:

Create a CDN

A CDN is a content delivery network and allows you to cache your website on servers that are geographically closer to your user base. This reduces response time exponentially and should be standard practice for anyone looking to scale their online business.

Optimize Your Database

Fetching the requested data from your database may be a difficult task for your server depending on what type of system and algorithm you are running. To improve a slow response time, make sure that your website is using the optimal system for your application’s needs.

Compress Media Files

Oversized media files can contribute to a slow website response time by overloading your server’s capacity. If you have multiple users on your website pulling 8k video files, your server and its bandwidth will not be able to respond to new incoming requests with acceptable speed. To reduce high response times, consider compressing your media files to a reasonable size and storing unused media in a separate location. 

Declutter CMS

A light and optimized content management system (CMS) will ensure your website runs smoothly. Specifically for WordPress users, using several outdated plugins at once will affect server performance and result in slow web server response times. Consider using fewer plugins and opting for an all-in-one solution to your needs.

Use Fast and Trustworthy Web Hosting

While some cheaper web hosting solutions may appear to have an offer you can’t refuse, much smaller web hosting providers do not have the security, bandwidth, or hardware to offer adequate performance. 

A reputable web hosting provider is worth the extra money as they guarantee these capabilities and generally offer great customer support if things go wrong. Limited bandwidth and hardware limitations are among the leading causes for high response times amongst smaller web hosting companies. The servers do not have the specifications to meet the demands of large-scale usage.

Monitor Your Website

The only way to keep your site healthy and secure is by monitoring your website and the server on which it’s hosted and addressing the issues that arise. Without a clear synopsis of the issue, a developer will spend his days blindly testing bits and pieces of his site or application when an issue occurs. 

There are many uptime monitoring tools to help determine if a website is constantly experiencing downtime, find the causes, and fix them. A simple solution to determine your availability would be a synthetic monitoring tool like Sematext Synthetics.

Interested in actively monitoring your website's performance?

Get our free ebook on Website Monitoring today.

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Discover more tips for website performance optimization.

Website Response Times Monitoring With Sematext

With Sematext’s uptime monitoring tool, you can create specific monitors that will test your website at different times from various locations around the world. They will report back on response times, performance metrics and alert you if any preset thresholds or errors are met.

Sematext Synthetics will allow you to understand how your website is performing under different scenarios by simply using a monitor that can simulate a transaction from a mobile device, a specific connection type like 3G or broadband, and can even simulate user interactions using a real Google Chrome browser. 

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