There are several technical issues hindering the Shopify site’s performance on mobile devices. On mobile, the site is below industry standard on all 4 of the primary website performance metrics.
The site’s performance is much better on desktop compared to mobile. It is below industry standard on 2 of the primary website performance metrics, but only by a little bit.
The poor website performance on mobile would have adverse affects on the site’s conversion rate, SEO, paid marketing performance, and customer experience.
I would recommend optimizing the Shopify site to perform better on mobile devices, which would also improve it’s performance on desktop. To learn more, click Next Steps.
Mobile Page Speed Audit
Check image below for numbering while following along.
Overview
The John Robshaw Textiles Shopify site is below industry standard in all four of the core website performance metrics on mobile devices.
The metric to pay most attention to is Largest Contentful Paint (LCP). This metric is the most common way to measure a page’s load time. It is a measure of how long until the site is full loaded for users. It currently sites at 10.8 seconds. The recommended LCP for ecommerce sites is between 2 - 3 seconds on mobile.
Poor LCP and other performance metrics can have negative effects on conversion rate, SEO ranking, paid marketing performance, and overall customer experience.
Results
First Contentful Paint: 2.7 seconds
Explanation: First Contentful Paint (FCP) measures how long it takes for content to start appearing on a website. This is typically an empty box or plain text. It’s the first pixels rendered in for the site.
Optimal time for ecommerce sites is < 1.8 seconds.
Largest Contentful Paint: 10.8 seconds
Explanation: Largest Contentful Paint (LCP) measures how long it takes for a website to display its biggest single content element. It's one of the most common ways to measure page load time.
Optimal time for ecommerce sites is < 2.5 seconds.
Total Blocking Time: 2,480 ms (2.48 seconds)
Explanation: Total Blocking Time (TBT) measures how responsive your site is to user input (i.e. if the user performs an action, such as click a button, how long before the next action can be performed).
Optimal time for ecommerce sites is < 0.3 seconds.
Cumulative Layout Shift: 0.11
Explanation: Cumulative Layout Shift is a measure of how “stable” your website it after it first renders. A website that has content shift down as more object load will have a higher score. Cumulative Layout Shift is one of the core ranking factors for Google.
Optime score for ecommerce sites is < 0.1.
Speed Index: 11.0 seconds
Explanation: Speed Index (SI) measures how quickly content appears on your website. The value is determined visually by analyzing screenshots of your website during the page load process. Speed Index is a lesser important metric comparatively; however, optimizing it will benefit the Largest Contentful Paint (LCP).
Optimal time for ecommerce sites is < 3 seconds.
Optimization
Accord to the PageSpeed results, there are 4 technical issues slowing down the website:
Reduce Javascript execution time
In short, this means that there is a substantial amount Javascript, HTML, and CSS code that is slowing down the site. There are four ways that Javascript code can accumulate on your site: when you connect a new Shopify app, when you use certain themes, when you use third-party scripts such as Facebook Pixel or Google Analytics, and if you have custom code on your site. The biggest culprit is Shopify apps. Each app “injects” a bit of code into your site. Even if the app is deleted, the code it injects stays behind. Over time, this code will slow down your site’s load time.
Minimize main-thread work
Main thread overload happens when too many tasks, like heavy JavaScript execution, complex CSS code, and third-party scripts, are processed simultaneously. This slows down the site’s load time. The best way to fix this is to delete unused Javascript, compress essential Javascript code, and remove unnecessary third party scripts.
Optimize Largest Contentful Paint (LCP)
The LCP takes up a considerable amount of main thread resources when loading. As a result, it needs to be optimized through image compression, preloading important page elements, and eliminating unused CSS and Javascript files.
Reduce the impact of third-party code
Third-party scripts, such as ads, analytics, and social media widgets, can slow down your site. Delaying the firing of analytics, or deferring them from using the main thread, can improve performance.
Desktop Page Speed Audit
Check image below for numbering while following along.
Overview
The website’s performance on desktop is much better than it’s performance on mobile devices. It performs below industry standard in only 2 out of the 4 core metrics, and only by a little.
The main metric to pay attention to on the web is Largest Contentful Paint (LCP), which was 2.1 seconds. This was barely above industry standard of 1 - 2 seconds on desktop.
Optimizing the site’s performance on mobile would benefit the site’s performance on desktop, and help boost desktop conversion rates.
Results
First Contentful Paint: 0.5 seconds
Explanation: First Contentful Paint (FCP) measures how long it takes for content to start appearing on a website. This is typically an empty box or plain text. It’s the first pixels rendered in for the site.
Optimal time for ecommerce sites is < 1.8 seconds.
Largest Contentful Paint: 2.1 seconds
Explanation: Largest Contentful Paint (LCP) measures how long it takes for a website to display its biggest single content element. It's one of the most common ways to measure page load time.
Optimal time for ecommerce sites is < 2.5 seconds.
Total Blocking Time: 180 ms (0.18 seconds)
Explanation: Total Blocking Time (TBT) measures how responsive your site is to user input (i.e. if the user performs an action, such as click a button, how long before the next action can be performed).
Optimal time for ecommerce sites is < 0.3 seconds.
Cumulative Layout Shift: 0
Explanation: Cumulative Layout Shift is a measure of how “stable” your website it after it first renders. A website that has content shift down as more object load will have a higher score. Cumulative Layout Shift is one of the core ranking factors for Google.
Optime score for ecommerce sites is < 0.1.
Speed Index: 3.4 seconds
Explanation: Speed Index (SI) measures how quickly content appears on your website. The value is determined visually by analyzing screenshots of your website during the page load process. Speed Index is a lesser important metric comparatively; however, optimizing it will benefit the Largest Contentful Paint (LCP).
Optimal time for ecommerce sites is < 3 seconds.
Optimization
Accord to the PageSpeed results, there are 4 technical issues slowing down the website:
Reduce Javascript execution time
In short, this means that there is a substantial amount Javascript, HTML, and CSS code that is slowing down the site. There are four ways that Javascript code can accumulate on your site: when you connect a new Shopify app, when you use certain themes, when you use third-party scripts such as Facebook Pixel or Google Analytics, and if you have custom code on your site. The biggest culprit is Shopify apps. Each app “injects” a bit of code into your site. Even if the app is deleted, the code it injects stays behind. Over time, this code will slow down your site’s load time.
Minimize main-thread work
Main thread overload happens when too many tasks, like heavy JavaScript execution, complex CSS code, and third-party scripts, are processed simultaneously. This slows down the site’s load time. The best way to fix this is to delete unused Javascript, compress essential Javascript code, and remove unnecessary third party scripts.
Optimize Largest Contentful Paint (LCP)
The LCP takes up a considerable amount of main thread resources when loading. As a result, it needs to be optimized through image compression, preloading important page elements, and eliminating unused CSS and Javascript files.
Reduce the impact of third-party code
Third-party scripts, such as ads, analytics, and social media widgets, can slow down your site. Delaying the firing of analytics, or deferring them from using the main thread, can improve performance.
It’s common for the same technical issues to affect the site on mobile and on the web. The issues are extenuated on mobile due to the lower processing power.
Next Steps
Anyone selling products on the internet should think about their website’s speed. It plays a major part in how effectively a website can turn visitors into paying customers.
found that a 0.1 second improvement in website speed can increase overall conversion rates by 8.4%.
Other sources have found interesting links between fast site speed and better SEO, lower cost acquisition costs when using paid ads, and an increase in repeat purchases.
Let’s make it real with an example. Let’s say an ecommerce site get’s 100,000 visitors per month and has a 3% conversion rate.
If that site is optimized for speed, and see a 20% increase in conversion rates, it would go from 3000 sales/month to 3600 sales/month. At an AOV of $30, that’s an addition $20,000 per month in sales for every 100,000 visitors.