Why Is Ulta So Slow? Here Is The Answer

Ulta is an Illinois-based beauty store chain that sells makeup, hair care, skincare, and fragrance products online

A speed report from Lighthouse paints a rather grim picture and scores the Ulta website 16.2 seconds on the speed index (SI), and 28 on Performance.

There are many reasons why the Ulta website is so slow. This includes:

  • Bloated JavaScript files
  • Unused CSS files
  • Render-blocking resources
  • Large DOM size
  • Ineffective Caching Policy

Let’s look at each of these reasons and identify potential ways that Ulta can make its website load faster.

But before we do that, a quick word about our website - we are a free email alert service that sends out notification any time your website is loading very slowly (often due to heavy traffic, or poor scripts). If you have a website, consider setting up an alert so that you can fix issues before they become major. 

Bloated JavaScript files

Ulta uses a lot of JavaScript to run the website. However, loading them all from one source could slow up the performance of the website. Ulta can avoid this by splitting the code into smaller files. This way, you only load files that are necessary.

The Ulta website can be as much as 5.83 seconds faster by adopting this technique.

Unused CSS files

Ulta uses CSS files to load the styling elements for the website. However, this file contains a lot of unused scripts that can be slowing down page loading by as much as 0.2 seconds. Code splitting may help avoid this issue.

Render-blocking resources

There are scripts on the Ulta website that need to run first before they let the rest of the code be executed. The render-blocking resources issue can shave off around 0.75 seconds from the loading time for the Ulta website.

How do you avoid this? If the script is not critical, avoid having it in the <head> tag of your HTML code. But if you do need to have it there for some reason, make sure to include the defer or async attribute so that they do not block the loading of other resources. 

Large DOM size

The Ulta website takes close to 34.5 seconds to evaluate all the scripts, parse them, compile, and render them. This can be minimized by minimizing the main-thread work.

They may also look at reducing the number of nodes in the DOM. In simpler terms, you need to make sure that the main HTML code is smaller and has fewer nodes. I have explained this in greater detail in this article about DOMContentLoaded.

Ineffective Caching Policy

A website like Ulta is made of several components, including a lot of images, and other media files. Caching, or storing these components in your local computer, enables your browser to load the website much faster when you come back a second or third time.

With Ulta however, the cache for most media files clear is deleted every 1 day. This means that the website is loaded completely from scratch any time you visit after 1 day. Enabling a longer cache period could make loading pages faster and more user-friendly.

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