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8 Key Strategies To Eliminate Render-Blocking Resources.

Render-blocking is one of the most tricky problems that most online websites face. This problem can waste a business’s time, money, and effort as it harms website traffics and sales.

Consequently, most businesses seek comprehensive solutions that can help them to address the problem.

This article will help you overcome this crisis by providing 8 key strategies to eliminate render-blocking resources. Thus, boosting your traffic and sales. Let’s explore!

Table of Contents

Render-blocking definition

Render-blocking is the delay in displaying visual elements on a website. Render-blocking often occurs when the rending process can only be carried on after a web browser loads and processes external resources. These external resources, such as CSS and JavaScript files, are essential for styling and interactivity on the web page.

What is render-blocking?

Render-blocking resources, including the scripts, stylesheets, and HTML imports, block the rendering of visual elements to the screen. When render-blocking resource occurs, a website may witness a slow initial page load, delay in interactivity, a blank or partially rendered page, and more.

Render-blocking resources can be both critical and non-critical. A critical one is required for a web page to render important content, while a non-critical one can interrupt page load time.

As a result, businesses must be able to identify the difference between these two types of render-blocking resources to find the best solution to minimize the risk of render-blocking.

How do render-blocking resources affect website performance?

The first issue that render-blocking resources most affect is the interruption in the website rendering process. When there are render-blocking resources on the website, the browser has to download and execute these resources before other processes can continue.

Hence, the rendering time of a web page can be extended as it has to wait until this scheme is finished. The extension in time can result in slower page load time and poor user experience.

More than that, the render-blocking resources can also affect customers’ page load time. When entering a website, users often evaluate its efficiency depending on its speed and the time to display visual content.

Consequently, if a website struggles with render-blocking issues, its perceived load time will also increase. Undoubtedly, this issue can frustrate users and give rise to bounce rates.

Render-blocking resources also hurt the website’s interactivity and responsiveness. One of the most common render-blocking resources is the JavaScript file, which plays a vital role in providing interactivity as well as functionality to the web page.

For this reason, many user interaction characteristics, namely button clicks or form submissions, will be blocked when JavaScript files are render-blocking. Thus, the website becomes unresponsive and negatively impacts user experience.

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5 Tools to identify render-blocking Resources

Render-blocking resources are common tricky problems for many online websites. However, many tools are also designed to help businesses recognize these issues. Here is the list of 5 most common tools to identify render-blocking resources for businesses:

Google Chrome DevTools

Google Chrome DevTools is a powerful collection of website development and debugging gadget attached to the Google Chrome browser.

This tool has many features and uses, such as a Network panel with the ability to display loading order resources, or an Audits panel, with the potential to carry on an audit and highlight render-blocking resources.

PageSpeed Insights

PageSpeed Insights is a tool developed by Google that has many usages, including recording and analyzing web page performance and providing suggestions for improvement solutions. This tool can recognize and indicate render-blocking resources among many different performance-related issues.

Moreover, it is also very friendly and easy to use as you only have to enter the website’s URL, which will immediately create detailed information and recommendation report for your website.


Lighthouse is an open-source application integrated into Google Chrome’s Developer Tools. This application automatically allows the user to examine a web page’s performance, accessibility, and SEO. Lighthouse can also outline render-blocking resources and advise solutions for each problem.

WebPage Test

WebPagetest is a free online tool that enables users to observe their website performance, regardless of location and browsers. This online tool can also develop a flying bricks chart that displays the loading order of resources, making recognizing render-blocking resources much easier.


Another popular online web performance testing tool is GTmetric.

This tool also has the potential to provide users with detailed insights into its loading speed. It can offer a business flying brick charts as well as a breakdown of resources about its web page performance. In addition, recommendations to optimize and improve website performance are also included.

8 key strategies to eliminate render-blocking resources

Render-blocking resources may waste businesses’ time, money, and efforts if the problems are not taken seriously.

However, businesses can minimize the risk of render-blocking resources as well as make the process of removing this issue more easily by consulting 8 key strategies to eliminate render-blocking resources below:

1. Analyze root cause

Analyzing the root cause is the first and foremost thing that should be done before tackling any problems. This is one of the best ways to identify and have a specific overview of what is happening.

There is also no exception for the render-blocking issue case. By tracking and analyzing the root causes beforehand, businesses will more likely determine which exact resources are causing the render-blocking issues. Some typical resources can cause render-blocking issues, including external stylesheets (CSS) and JavaScript files.

By analyzing the main reason for render-blocking resources, you can make a great decision in solving problems and improving your page Core Web Vitals.

2. Optimize CSS and Javascript files

External stylesheets (CSS) and Javascript files have been considered common render-blocking resources that can negatively affect a web page. As a result, if the tracking of CSS and Javascript files is not taken seriously, they can become an intangible risk and deteriorate web performance.

CSS and Javascript files can become a tangible risk for web performance

One of the most common solutions to removing these render-blocking resources is to do it manually. However, this can only be an ideal option if the person taking charge of removing render-blocking resources is an experienced coder.

This process can also be very functional in decreasing the number of plugins on a website. An async or defer attribute can be added to the files when optimizing JavaScript files. This process will help highlight non-critical scripts so that the browser can display them individually.

3. Implementing browser caching and CDN

Implementing browser caching and Content Delivery Networks (CDN) can be a great option when eliminating render-blocking resources due to their positive impacts.

For example, when users first visit a website, the browser caching will help to store important resources, namely CSS files, images, JavaScript files, etc. This storing process will play a vital role in the next access time of a customer as the browser will no longer have to make a new request. Instead, it can utilize the resources from its cache.

Consequently, this will remove render-blocking resources as the number of requests is decreased, and the time for these resources to be downloaded is also eliminated. Take a look at Magento 2 Block Cache for further approaches to caching.

As for Content Delivering Networks (CDN), when using a CDN to deliver a website’s static resources, these resources, such as CSS, JavaScript, and images, are stored in the CDN’s server.

When the user requests the web page, the cached resources closest to the user will be displayed, thus reducing the discontinuation and network congestion. More importantly, this also prevents the user’s browser from waiting to download render-blocking resources from the origin server.

4. Prioritize critical resources

Prioritizing critical resources can be a key solution because it can hold a high commitment that only essential resources required for rendering visible parts of the webpage are loaded and processed in advance.

Prioritize critical sources can be a key solution

As the browser can render and display above-the-fold content quickly and efficiently, users will immediately see the website’s fast loading speed. More than that, by prioritizing critical resources, the impact of render-blocking resources can be eliminated or minimized. The necessary styles and scripts will be prioritized to be loaded and rendered first, resulting in the website’s interactivity and usability for users.

It is undeniable that this approach is beneficial for a web page in numerous ways, such as enhancing perceived loading speed, quick user interaction with vital parts of the page, and more.

5. Enhance nonsynchronous JavaScript loading

The synchronous loading of external resources, including JavaScript files, often interrupts the parsing and rendering of HTML before the resource is fully loaded and accomplished. Thus, this will lead to a significant delay in the page’s rendering process as well as a slower user experience.

Nonsynchronous JavaScript loading, as a substitute, allows the browser to fetch and load those resources in the background while parsing and rendering the rest of the page, using attributes like “async” in script tags. Before the external resources are finished loading, the rendering process will not be delayed, and the user can still see and interact with the content on the website.

Furthermore, this can speed up the loading process, especially for resources that are not directly critical for the initial rendering of the page. With asynchronous loading, the browser can retrieve the resources without waiting for one resource to finish before starting the next, reducing the overall loading time.

6. Delay non-critical JavaScript

Deferring non-critical JavaScript assists businesses in removing render-blocking resources by allowing a continuous process of parsing and rendering the web page by the browser without being paused by the execution of those scripts.

You can consider delaying non-critical JavaScript by moving the non-critical JavaScript files to the end of the HTML, just before the closing </body> tag. This allows the page content to be rendered by the browser first, without being blocked by JavaScript execution.

By delaying non-critical JavaScript, the rendering process is optimized, render-blocking resources are removed, the loading speed is improved, and users can access and interact with the content more quickly.

7. Evaluate third-party scripts

Evaluating third-party scripts can contribute to the process of removing render-blocking resources by recognizing and eliminating unnecessary or poorly optimized scripts that harm the rendering process.

You can start examining third-party scripts by reviewing and assessing the necessity of third-party scripts on your website. Each additional script can have its tangible render-blocking resources and affect web performance. Remember to keep the essential scripts for your site’s functionality.

By evaluating third-party scripts, the root causes contributing to render-blocking resources will be identified and addressed more efficiently.

8. On-going test and measure of performance

Ongoing tests and performance measures can help eliminate render-blocking resources by providing an overall report into the contemporary state of the web page’s loading speed as well as recognizing specific areas that need to be optimized.

On-going tests and measures of performance can eliminate render-blocking resources

Insights, GTmetrix, or WebPageTest. These tools will provide detailed insights and recommendations for further optimization.

By ongoing testing and measuring performance, you will gain valuable insights into the effect of render-blocking resources on your website. This process also ensures that informed optimization decisions, and progress tracking are made to the website, and optimal web loading speed is maintained by removing or minimizing the impacts of render-blocking resources.

Wrap up

Undeniably, render-blocking resources have many negative impacts on website performance, such as slower page loading time, increase in bounce rate, poor user experiences, and more.

Consequently, businesses should focus on tracking and eliminating render-blocking resources as it is the most efficient way to reduce the impact of this issue and rocket their website’s traffic and sales.

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Hello, I'm the Chief Technology Officer of Mageplaza, and I am thrilled to share my story with you. My deep love and passion for technology have fueled my journey as a professional coder and an ultra-marathon runner. Over the past decade, I have accumulated extensive experience and honed my expertise in PHP development.
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