4 Effective Ways To Eliminate Render Blocking Resources To Improve The Pagespeed Performance

“Eliminate render-blocking resources” is one of the most common warnings you may come across while analyzing the website’s PageSpeed performance in Google PageSpeed Insights. The render-blocking resources can slow down your website’s PageSpeed and affect the Core Web Vitals.

Render Blocking resources

Now, you may be wondering how to solve the “Eliminate render-blocking resources” warning and improve the PageSpeed performance score of your website. Here, we will discuss what are render-blocking resources and the effective ways to eliminate render-blocking resources to improve your Core Web Vitals.

What Are Render-Blocking Resources?

During web page rendering,a process where the browser creates the website from the codes & images on the website, a browser needs to go through processes that includes loading and parsing (executing) various resource files such as HTML, CSS, JavaScript, and media files (images and video). 

Render-blocking resources are those that delay the browser rendering of the page content on visitors’ screens by blocking the main thread. If a browser comes across a render-blocking resource, the entire critical rendering path is put on hold and the visitor would see a delay in loading the website completely.   

Render blocking resources network header

Let’s understand the render-blocking resources with an example. Assume a javascript could be a render-blocking resource for your website, which by default they are. That indicates when the browser comes across that Javascript file; it holds the rendering process until the render-blocking Javascript file is fully executed. 

During that time the browser would not be able to do the tasks needed to show the webpage to the visitor.Therefore, it would harm the PageSpeed performance of your website.   

Type Of Render-Blocking Resources

The browser considers linked CSS & javascript files in the <head> tag in the HTML file as a render-blocking resource that includes:

  • CSS stylesheets
  • Any scripting file such as JavaScript in the <head> tag
  • Web fonts 

Note: any media files in the <body> section of the HTML file are considered a non-critical resource. 

The Importance Of Eliminating Render-Blocking Resources

By eliminating render-blocking resources, you can significantly minimize the critical rendering path which leads to reducing your website’s page loading time. 

Pagespeed performance

A Google PageSpeed Insights score based on the five performance metrics that have different weights:

  • First Contentful Paint (FCP): 10%
  • Largest Contentful paint (LCP): 25%
  • Total Blocking Time (TBT): 30%
  • Cumulative Layout Shift (CLS):  25%
  • Speed Index (SI): 10% 

If your website has a large number of render-blocking resources, it can typically harm these performance metrics, leading to a poor Google PageSpeed Insights score. Eliminating render-blocking resources can positively impact your Core Web Vitals, resulting in a good PageSpeed score. 

Therefore, if you are struggling with a poor PageSpeed score, you must take steps towards eliminating render-blocking resources from your website. 

The Effective Ways To Eliminate Render Blocking Resources

Eliminating the render-blocking resources is one of the most essential web optimization techniques that Google PSI suggests to improve the PageSpeed score. Removing these render-blocking resources can be the most challenging process, as it needs a lot of technical knowhow.  

The best course of action would be to  install an optimization tool like RabbitLoader. However, if you want to explore the Do It Yourself route, you can follow the below strategies, which include:

  • Splitting The Code And Deferring Non-Critical JavaScript 
  • Minify CSS And JavaScript Files
  • Generating Critical CSS

Splitting The Code And Deferring Non-Critical JavaScript

Code splitting is an effective technique to eliminate render-blocking resources and optimize the render-blocking path. It allows you to break a large JavaScript file into small JavaScript chunks. 

Most of the JavaScript functions are not required for the initial page loading time. These JavaScript functions are considered render-blocking resources. By deferring these JavaScript functions, you can significantly eliminate the render-blocking resources from the critical rendering path

Deffer javascripts

For this, you need to manually identify your non-critical JavaScript function and add a defer attribute in the HTML file.


<script src="non-critical.js" defer></script> 

You can easily avoid these coding endeavors by just installing RabbitLoader. When you use  RabbitLoader, it will take care of every optimization technique required to supercharge your website along with the technique to eliminate render-blocking resources. 

Minify and Compress CSS And JavaScript Files

Most web developers use line breaks, comments, and white spaces to increase the readability of the coding file. However, these characters are considered unnecessary characters by a browser. However, when a browser parses the coding file, these characters increase the web page’s file size.

Compress resources

Minification is a method to delete unnecessary characters from your code without harming their functionality. Compressing is the method by which you can easily replace the repeated string variables with a single pointer. Please visit our minify resources blog.

For a large website, manual minification and compression can be daunting for you. For an effortless solution, you should try installing RabbitLoader. 

Generating Critical CSS

Generating critical CSS removes the render-blocking resources and improves the LCP and INP performance by creating a separate CSS file for critical CSS. 

To manually do this, you need to first identify your critical CSS and then make a separate file for this. Read the critical CSS blog to learn more about this. 

While most optimization tools avoid this technique, RabbitLoader can successfully reduce the CSS file size by 90% in most cases by generating critical CSS. Let’s see with an example.

Critical CSS optimization

Here, RabbitLoader reduced the CSS file size to just 39.4 kb from 2.3 Mb. And you can see the improvement. The average page rendering time is significantly reduced from 10950.5 ms to just 287.8 ms. 

Eliminate Render Blocking Resources With RabbitLoader 

Mitigating the Google PageSpeed Insights warning “Eliminate render-blocking resources” can be daunting if you are trying to do this by yourself, especially if you are from a non-tech background.  

Instead try using RabbitLoader, it will perform all the necessary techniques that are essential to eliminate render-blocking resources and optimize your website’s PageSpeed performance. As a result, you can pass the core web vitals assessment and improve the Google PageSpeed Insights score. 


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