LinkedIn is the biggest professional social network and is now owned by Microsoft. It has over 930 million registered users, and according to SimilarWeb receives more than 1.7 billion visits each month.
A speed report from Lighthouse paints a rather grim picture and scores the LinkedIn website 5.7 seconds on the speed index (SI), and 39% on Performance.
There are many reasons why the LinkedIn 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 LinkedIn can make its website load faster.
But before we do that, a quick word about our website CWVIQ.com - 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
LinkedIn uses a lot of JavaScript to run the website. However, loading them all from one source could slow up the performance of the website. LinkedIn can avoid this by splitting the code into smaller files. This way, you only load files that are necessary.
The LinkedIn website can be as much as 1.6 seconds faster by adopting this technique.
Unused CSS files
LinkedIn 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 0.32 seconds. Code splitting may help avoid this issue.
Render-blocking resources
There are scripts on the LinkedIn 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 2.01 seconds from the loading time for the LinkedIn 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 LinkedIn website takes close to 6.2 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 LinkedIn 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 LinkedIn however, the cache for most media files clear is deleted every 7 minutes. This means that the website is loaded completely from scratch any time you visit after 7 days. Enabling a longer cache period could make loading pages faster and more user-friendly.
Anand Srinivasan is the founder of CWVIQ, and has been in the internet media space for over 15 years. He has previously served as the AVP of Products and Head of Business at popular media portals. He has worked with several SaaS and enterprise businesses as an external consultant for their SEO marketing campaigns.
None of this is specific to LinkedIn. A waste of my time
As mentioned in the article, LinkedIn takes an extra 1.6 seconds to load because of bloated JS, and another 2.01 seconds because of render blocking resources. We have also listed other factors that can potentially help LinkedIn load faster.