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Apr 20, 2023 | 7 minute read

Why Site Performance Matters and How to Improve It

written by Emily Kathi

Site performance (or lack thereof) is one of the biggest pain points eCommerce businesses face today, due in part to its direct correlation to conversion rate. If you don’t think site performance matters to your customer - your revenue, and your reputation, are at risk.

I’ll cover why site performance matters and how best to improve it if you find yourself on the slower end of the speed trial.

Consider this:

  • It takes about fifty milliseconds, or .05 seconds, for users to form an opinion about your site and determine if they will stay or go. Think about your personal experience with a slower-paced load time on a site. How many times have you bounced off as quickly as you found it? From ordering a pizza to buying a couch, today’s consumer simply does not have time to wait.
  • Fifty-seven percent  of internet users say they won’t recommend a business with a poorly designed web application on mobile.

Given the miniscule timeframe to make a good first impression on a consumer, plus the hefty influence of word-of-mouth first impressions by those same consumers (either favorable or less than), site performance is not a “nice to have,” it is critical.

Poor site performance is expensive. Industries may vary as far as numbers, but let’s see on average what the damage looks like when it comes to what slow site speed will cost you. For example, if you’re running an ecommerce site that makes $100,000 per day, a one second page delay could  cost you $2.5 million  per year in lost sales. To put that in eCommerce behemoth terms, let’s take Amazon. Performance tests showed they would lose $1.6 BILLION every year if they slowed down by just one second.

What is the Benchmark for Optimal Site Speed?

The Google-recommended page load time is under  two seconds. Two seconds is the threshold for ecommerce website acceptability, while Google aims to keep load time under a half-second. Additional food for thought: 47% of consumers expect a page to load in two seconds are less, while studies show for every 100ms decrease in home page load speed results in a 1.11% lift in session-based conversion.

Other factors that affect site performance to keep in mind: mobile device usage, bandwidth, and variable internet speeds by user region.

So now that you’re aware of the high stakes of slow site speed, the good news is you have options for improving it. First things first, always be testing.

Web Application Performance & Speed Testing Tools

There are many products and services in the market to diagnose web application speed and performance. It’s important to have a clear picture of how your site is performing and be able to make tweaks quickly and easily. More benefits to these tools include:

  • Find out how your site is performing across devices. Most users are visiting through a mobile device so optimization is key
  • See how your site is performing across regions and countries
  • Analyze and optimize for better rankings and UX
  • Triage bottlenecks and make optimization decisions based on ROI and conversion rates

Interested in Learning More About Elastic Path Commerce Cloud?

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The Top Web Performance/Speed Testing Tools:

Pingdom Speed Test


Google PageSpeed Insights

Yellow Lab Tools

WebPage Test

KeyCDN Website Testing Tools



IsItWP Website Speed Tool


Figure 1: A typical Web Performance Tool interface Source: Pingdom

Next Steps: How to Improve on Speed and Overall Performance

Now that you’ve invested the time in the proper tools to monitor and improve site speed, and understand the slim window to keep a user engaged and on the path to purchase, here are a few things to consider that affect speed:

Dynamic vs. Static Content Management – The difference between the two is dynamic content is anything subject to change based on user input such as product, pricing, or descriptions. This content is stored in a database and is fetched when the user engages with it, otherwise known as async communication. Static content on the other hand is anything remaining the same in the experience such as the navigation menu. Both types of content have distinct yet crucial functions on a site but are managed differently.

While static content typically loads faster there are ways to manage dynamic content to alleviate issues and slower load times. As you edit dynamic content you want to avoid editing the HTML code as this will cause breaks in your site. Additionally when managing dynamic content use proper caching and Content Delivery Networks (CDN) to bridge the gaps between dynamic and static content.

Use a Faster Website Host – upgrading your website host can significantly affect your site speed. While you’d also be looking at site uptime, traffic volume (especially the ability to manage spikes during peak activity), customer support, and of course price. Here is a helpful Top 10 list of vendors to get started. You’ll want to review many providers and continuously comparison shop especially as you scale your business.

Image Optimization - no surprise that visual content engages users. However, high quality imagery means larger files that eat up load time. Using resized and compressed files is a lighter lift for the server to load the image.

Within imagery you’ll want to pay attention to the file format. There are four file types: PNG, JPEG, GIF, WebP, and SVG. A general rule of thumb is to avoid GIFs since they do drag on site speed. When choosing between PNGs and JPEGs, PNGs work well for graphics and screenshots, while JPEGs are ideal for photographs. The newcomer is the SVG file format, or scalable vector graphic that renders well in web applications and across other use cases. Lazy load plugins are also useful to only render photos where the user is browsing.

Reduce HTTP Requests – HTTP requests occur when the browser sends a request to the server for information. The fewer requests a website must make the faster the site can load. The amount and the size of the requested files affects load times, however most engaging sites have both multiple and larger files. The best way to address this issue and is to run a full report on your site and assess what images are taking the longest to load and if in fact you need them. After you assess what’s needed, you can reduce the file size.

Web Application Optimization is a Team Effort

Web application design and management is a collaborative effort between IT and marketing teams. You’ll want to consider the user experience but also look at the technical load of what you’re providing to the user. Poor site speed results in bounce rates; essentially all the work you put into an engaging interface is null and void if the load times are sluggish. It takes the unique roles and goals of each side to create a memorable experience that consistently drives conversion.