Boosting Your WordPress Website Performance With Critical CSS

Critical CSS plays a crucial role in mitigating the most common Google PageSpeed Insights warnings “Eliminate render-blocking resources” and “reduce unused CSS” and it also boosts your website’s page speed for a better user experience.

Identifying critical CSS (also known as critical CSS rendering path or critical path CSS) can be very challenging, especially for those without a technical background. 

Critical CSS, CSS

To make life a little easier for you, we will explain critical CSS, its impact on the website’s page speed, and how to identify your critical CSS. 

We will also explore how RabbitLoader can help you optimize your page speed by generating critical CSS for your website.  

What Is Critical CSS?

Critical CSS refers to the optimization technique of extracting the style rules or stylesheets applied to the above-the-fold elements to render the page quickly. 

You can add your CSS style sheets in two ways: External CSS (which is located in a separate file) and Inline CSS (located in the <head> tag in the HTML file). This external CSS file is considered the render-blocking CSS. Let’s understand why.


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First, the browser needs to load and parse the entire external CSS files to render your web page. This makes your external CSS file a render-blocking resource and reduces the web page loading speed.  

By generating critical CSS for the above-the-fold contents and inlining it in the <head> tag of the HTML file, you can extract critical CSS needed to render the content in the visible area or viewport. This reduces the size of the CSS file, increasing your website’s page speed.

The Impact Of Critical CSS on Your Website’s PageSpeed

As discussed, the CSS critical path improves your page loading time by inlining the necessary CSS styles (for rendering above-the-fold content) into the HTML file. Critical CSS rules have several benefits:

  • Enhance your user experience.
  • Reduce the render-blocking resources.
  • Improve the LCP performance.
  • Decrease HTTP requests.
  • Improve the overall page speed score

Enhance Your User Experience

According to Hubspot, a website that takes less than 1 second to load converts 2.5x more users than a site that loads in 5 seconds. Therefore, a website with a good PageSpeed performance can enhance the user experience, increasing the conversion rate.

User Experience

Critical path CSS can improve your website’s loading time, which can positively impact your user experience and conversion rate. 

Reduce The Render-Blocking Resources

By adding only critical CSS inline, the browser can render only the above-the-fold content without parsing the entire CSS file. Therefore, eliminating these render-blocking resources improves the Time to First Byte (TTFB), enhancing the user experience.

Render Blocking Resources, Critical css

Improve The FCP Performance

First Contentful Paint (FCP) is a user-centric metric that measures how fast your website’s content is rendered on the user’s browser. Critical path CSS ensures that the first content is rendered as quickly as possible, leading to a better FCP performance.

First Contentful Paint

Decrease HTTP Requests

By generating critical path CSS, you can reduce the number of HTTP requests required to render the initial page loading time. Fewer HTTP requests indicate faster loading time, increasing the average on-page time of your website.

https requests

Improve the Overall PageSpeed Score

Google PageSpeed Insight scores depend on the core web vital metrics. By generating the critical CSS file, you can improve the performance of your core web vitals, especially First Contentful Paint (FCP), and Time to First Byte (TTFB). Therefore, the overall PageSpeed score would be improved.

Critical CSS, overall pagespeed performance

How To Identify Your Critical CSS?

Determining the proper inline CSS for a web page can be very difficult due to different screen sizes, such as mobile, tablet, and desktop. Here, the ultimate goal is to divide the entire CSS file into critical CSS and non-critical CSS.

To extract critical CSS manually, you need to follow the below steps:

  • Open every web page in the browser such as Google Chrome. 
  • Right-click on the page and select Inspect or press F12.
Browser Inspect,  Critical CSS
  • Click on the three dots and select Coverage from the more tools. Then reload the page.
coverage, critical css
  • In the usage visualization section, you can see the non-critical CSS (red) and critical CSS (grey).   
Critical- Non-critical, css optimization
  • You need to create a separate file and extract critical CSS rules.  
  • After identifying critical path CSS, inline CSS style by adding this in the <head> tag in the HTML document. Load the non-critical CSS asynchronously (deferred loading). 

To extract critical CSS, you need to continue the above steps for each web page. This process consumes a lot of time and effort, so you must use an online critical CSS plugin like RabbitLoader. 

FAQ: How to add inline CSS?

Inline CSS is used in the <Style> tag in the HTML file.


<h1 style="color:blue;">example of inline CSS</h1>

Generating Critical Rendering Path With RabbitLoader

Let’s explore how RabbitLoader optimizes your website speed as a critical CSS extractor and critical CSS generator. When you are using RabbitLoader for site speed optimization, you don’t need to put in any extra effort. 

RabbitLoader identifies your website’s critical CSS and generates a separate file. As you can see in the images below, the original CSS file is 2.3 MB. However, RabbitLoader reduced the CSS file size to only 40.7 KB by generating critical path CSS and improved the file size by 98%.

You can also see the page rendering time before and after generating critical CSS. Here, it is just 294.1 ms, down from 11340.1 ms.   

CSS Optimization, critical CSS,

The advantage of RabbitLoader over other optimization tools is its all-in-one optimization features. In other words, when you use RabbitLoader, you don’t need to use any other optimization tools to implement lazy loading, link preload, fetch priority, and other optimization techniques.

Additionally, RabbitLoader has a free version, which gives it an advantage over the other optimization tools.


At this point, it’s clear that generating inline CSS is one crucial optimization technique for improving your website’s load time. However, manually generating this critical CSS can be daunting, especially when your website is large.

Thankfully, RabbitLoader is there to help. As we discussed, it optimizes your CSS file by 98% and speeds up web page rendering time by 90%-95%.

So, if you also notice “Eliminate render-blocking resources” or “reduce unused CSS” warnings during your page speed audit in Google PageSpeed Insights, it’s high time to install RabbitLoader and boost your PSI scores.


Get The Best PageSpeed Score

For Your WordPress Website

All in One Optimization Plugin
No Coding Knowledge Required

Google Pagespeed Insights: The Ultimate Guide To Boost Your Pagespeed With The 7 Most Powerful Strategies

Are you struggling with a low pagespeed insights score?  A low pagespeed score often leads to poor user experience which in turn results in a low conversion rate & lower SEO rankings.

Don’t worry! You are not alone. A lot of website owners are struggling to improve their pagespeed insights score. Let’s discuss the pagespeed insights score and the powerful strategies to improve this. 

Pagespeed Insights

If you are not from a coding background, that’s perfectly fine. As we will mention the solutions that can be implemented by non-coders like you and me

What is Google Pagespeed Insights?

Google PageSpeed Insights (PSI) is a tool developed by Google, that measures the pagespeed of your website. It analyzes your website’s pagespeed performance for the desktop version and the mobile version and scores on a scale of 0 to 100.

Pagespeed Insights

Google PageSpeed Insights also suggests how to improve the pageSpeed score. It provides both lab and field data about your website. Lab data is used for debugging issues whereas field data is useful for real-world user experience.

What are the Core Web Vitals?

Core Web Vitals are a set of performance metrics developed by Google, used to measure the user experience for loading performance, visual stability, and interactivity of your web pages. 

core web vitals

Let’s take a look at the three pillars of core web vitals

  1. Largest Contentful Paint (LCP)
  2. First Input Delay (FID) is now replaced with Interaction to Next Paint (INP).
  3. Cumulative Layout shift(CLS) 
  • Largest Contentful Paint (LCP):

The Largest Contentful Paint (LCP) is the user experience (UX) metric, which measures how long it takes to render the largest piece of content in the visible area. The largest content can be:

  • Images
  • Video poster images (images that are shown to the user before loading the video)
  • Background images
  • Block-level text
Largest contentful paint, lcp

In order to pass the Core Web Vitals assessment, your website should have a Largest Contentful Paint (LCP) of 2.5 seconds or less. Whereas if a user waits more than 4 seconds on your website to see the content, that indicates a poor user experience.

LCP rangeRemarks
< 2.5 secondsGood
2.5 seconds – 4.0 secondsImprovement Needed
> 4.0 secondsPoor
  • First Input Delay (FID):

First Input Delay (FID), also referred to as Input Latency, is used to measure how long it takes for your web page to react to the first interaction

In simple words, it is the measurement of the time that occurs between when a user interacts with your website and when their browser responds. 

First Input Delay,fid

According to Google, a score of less than 100 milliseconds is considered a good score whereas a score is more than 300 ms is a poor score.

FID rangeRemarks
< 100 msGood
100 ms- 300 msImprovement Needed
> 300 msPoor

Important Note: In March 2024, FID was removed as a Core Web Vital. It is replaced by a stable Core Web Vital metric INP (Interaction to Next Paint).   

  • Interaction to Next Paint (INP):

Interaction to Next Paint (INP) is a newly launched performance metric by Google that is used to measure user interface responsiveness.

In simple words, Interaction to Next Paint focuses on measuring your web page’s response according to user interaction with the website.

Interaction to Next Paint, inp

Similar to the other performance metrics, the INP score can be in one of the three thresholds. A good INP value should always be within 200 milliseconds.

INP rangeRemarks
< 200 msGood
200 ms- 500 msImprovement Needed
> 500 msPoor
  • Cumulative Layout shift(CLS):

Cumulative Layout Shift (CLS) is one of the pillars of Core Web Vital metrics that calculates the shifting of the webpage’s elements while the page is being loaded and rendered.

cumulative layput shift,cls

In simple words, Cumulative layout Shift is used to determine the visual stability of a web page from a user perspective by considering the below factors:

  • Layout shift
  • Impact fraction (how an unstable element impacts the visible area between two frames)

You should strive to reach your CLS score within 0.1 to provide your audience with a better user experience.

CLS rangeRemarks
< 0.1Good
0.1 – 0.25Improvement Needed
> 0.25Poor

Other performance metrics are present that impact your website’s pageSpeed insights performance.

  • First Contentful Paint (FCP):

First Contentful Paint (FCP) is a user-centric metric that is used to measure how long it takes for a user’s browser to load DOM elements (images, videos, text, etc) of your web pages.

First contentful paint, FCP
FCP rangeRemarks
0 – 1.8 secondsGood
1.8 seconds -3.0 secondsImprovement Needed
> 3.0 secondsPoor
  • Speed Index (SI):

Speed Index (SI) is a web page load performance metric, that measures how quickly the contents of your web pages are visibly populated. SI is dependent on the size of the visible area.

Speed index, SI
SI rangeRemarks
0 – 3.4 secondsGood
3.4 seconds – 5.8 secondsImprovement Needed
> 5.8 secondsPoor
  • Total Blocking Time (TBT):

Total Blocking Time (TBT) measures how long your web page responds to specific user input. Several factors can be the reason for TBT like poorly optimized code, excessive plugin use, server performance, and large file sizes.

Total Blocking Time,tbt
TBT rangeRemarks
0 – 200 msGood
200 ms – 600 msImprovement Needed
> 600 msPoor
  • Time to First Byte (TTFB):

Time to First Byte (TTFB) measures the time between a user’s browser requesting your web page and when it receives the first byte of information from the server. Different factors that can reduce your TTFB score: slow DNS lookups, SSL connection, and so on.

time to first byte,ttfb
TTFB rangeRemarks
< 800 msGood
800 ms – 1800 msImprovement Needed
> 1800 msPoor
  • Time to Interactive (TTI):

Time to Interactive (TTI) measures the amount of time your website has been rendered and is ready for user input. The factors that significantly impact TTI are excessive resource requests and large resource sizes.

Time to Interactive,tti
TTI rangeRemarks
0 – 3.8 secondGood
3.9 second – 7.3 secondImprovement Needed
> 7.3 secondPoor

Why is Google Pagespeed Insights score important for your website?

Let’s dive into the importance of a high Google PSI score for your website.

  1. User Experience

A higher pagespeed Insights indicates a fast-loading website, which leads to a better user experience for your visitors. A user is more likely to engage with your website’s content and stay longer on your website. It will increase the average on-page time of your website.

pagespeed score
  1. SEO Ranking

Google considers the pageSpeed as one of the important factors in its ranking algorithm. A fast-loading website tends to rank higher in  SERPs (Search Engine Results Pages), which can boost organic traffic.

  1. Conversion Rate

The conversion rate measures the percentage of visitors who convert to lead. A fast-loading website can positively impact conversion rate, as users are more likely to complete the desired action.

Conversion rates

The desired action might be completing a purchase, downloading an ebook, filling up a form, signing up for a trial, booking a demo, subscribing to a course, or something else.

How to Measure Your Website’s PageSpeed Insights Score?

PageSpeed can be measured easily in Google  Pagespeed Insights (PSI). Let’s dive into the process of measuring PageSpeed in Google PSI.

Step 1: Go to Google PageSpeed Insights. Enter any web page’s URL and click on Analyze.

Pagespeed Insights

Step 2: After analyzing the web page’s page speed performance, It will provide a mobile score as well as a desktop score based on the overall performance of the core web vital matrix. 

Step 3: you can also see the suggestion for improvement of the pagespeed performance.

What is considered a good PageSpeed Insights Score?

  1. If the PageSpeed insights score is greater than 90, it is considered a good score.
  1. A Pagespeed insights score between 50 to 89 indicates the webpage’s pageSpeed performance needs to be improved.
  1.  A pagespeed insights score of less than 50 is categorized as a poor score. It means the web page fails the site speed test.
PageSpeed Insights Score

The Chrome User Experience Report (CrUX) dataset provides Real-user experience data in Google PSI. PSI reports are based on real users’ FCP, LCP, FID,  CLS, SI, TBT, and TTI experience.

Let’s see the weightage of each performance metric for Google pagespeed insights.

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

There are several alternative tools are also available like GTmetrix, and Lighthouse that you can use for website speed tests. 

The difference between Pagespeed insights vs lighthouse

While Google PageSpeed Insights and Google Lighthouse, both tools are used for pagespeed performance, their scores differ based on certain factors. Let’s understand these performance factors and how they make the score different. 

Google PSILighthouse
Data Sourcing MethodsGoogle PSI scores are based on controlled environment data(lab data) as well as real-user data (field data).Lighthouse uses only lab data. (real-user data).
Test LocationGoogle page speed Insights is an automated tool that runs from the Google server.Lighthouse is a manual tool that runs from a local Chrome browser.
Number of pages AccessedIn PSI only one webpage can be analyzed at a time.In Lighthouse, multiple pages can be tested at a time.
Network ThrottlingGoogle Pagespeed insights runs the website without throttling a fast network connection.

Then, it simulates how the web page would have loaded on the slow connection.
Lighthouse in Chrome DevTools allows a user to select between simulated and browser-level “applied” throttling. 
CPU performancePagespeed Insight measures the CPU performance of a web page by evaluating the time to fully load the web page’s content (HTML, JavaScript, and media files).Lighthouse reports include the data on the web page’s CPU performance, FCP, and DOMContentLoaded time.
Chrome versionPagespeed insights uses the latest version of Google Chrome. So it can be different from the user’s Chrome version.While Lighthouse uses the same Chrome version as the end user. 

7 ways to improve your website’s pagespeed score?

Now, you have a brief idea about Google PageSpeed Insights score. Also, you have seen the importance of a high pageSpeed insights score. Let’s dive into the strategies to improve the page speed performance by optimizing the website performance.

  1. Optimization of all images is the most effective way to improve your website’s pagespeed score:

Images are the most powerful form of communication. An image can convey a message very quickly. So, for any website, images are one of the essential resources.

However, large-sized images can decrease the pagespeed insights performance score by increasing the load time of the web page. 

To improve the website’s pagespeed performance, you need to reduce the image size as much as possible. You can convert your large image files to WebP, AVIF format.

If your website has 10 images of 2 MB, that indicates a total of 20 MB images need to be downloaded. But when these images are converted in WebP and AVIF, it will likely reduce the total size to a maximum of 500 KB. so, automatically the page loading time will be reduced.


RabbitLoader converts your large PNG and JPEG images into modern webP and AVIF formats. It will compress the images without losing quality. You don’t need to optimize the images one by one. Bulk image optimization will be done automatically when you are using RabbitLoader. 

If you have a WordPress website, you just need to install and activate this plugin. Apart from the WordPress website, RabbitLoader is also available in Woo-Commerce, Shopify, PHP, and Laravel websites.

  1. Minification of HTML, CSS, and JavaScript files can reduce page loading time:

HTML, CSS, and JavaScript are the fundamental elements of any web page. HTML creates the content of a webpage whereas CSS Stylshhets make the webpage stylish. And finally, JavaScript is used to make the webpage interactive.

Usually, the file sizes become large due to unnecessary uses of spaces & comments in the code to make the code more readable. These large files increase the page load time.

minify css,js,pagespeed insights

Minification is the process of removing all unnecessary spaces, Comments, and characters from a file. When a file is minified, the file size will reduce, which leads to a faster loading website. 

The best way to effortlessly minify these files is by using RabbitLoader if you don’t have any coding knowledge. RabbitLoader will manage this minification of your HTML, CSS, and JavaScript files.

  1. By enabling lazy loading you can improve your pagespeed insights score:

RabbitLoader will also help you to speed up your website by enabling lazy loading. Lazy loading (also known as on-demand loading) is an optimization strategy to improve the website’s performance if your website has a lot of images. 

lazy load,pagespeed insights

Instead of loading the entire webpage, Lazy loading only renders the images that are visible above the fold

Lazy loading also is applied to other media files such as videos, and the webpage’s content like text as well as comments. 

  1. Using browser cache to speed up your website:

Browser caching is the most common optimization technique. Browser caches temporarily store the static resources of a web page such as HTML files, CSS Stylesheets, images, and scripts. So, the browser doesn’t need to load from the first to render a web page. 

Let’s understand with an example.

  • You are visiting for the first time.

  • Your browser downloads the static contents(images, CSS stylesheets, JavaScript) into the cache.

  • The next time you revisit, these static contents are loaded from the browser cache. 

  • Thus, significantly decreasing this loading time.

Implementing a browser cache manually requires a lot of time as well as effort. There are several cache plugins available like RabbitLoader, W3 total cache, and many more. 

However, when you are using RabbitLoader for other optimization techniques, then why do you invest extra money in other cache plugins? RabbitLoader will also take care of this browser caching.

  1.  By Generating Critical CSS you can improve your website’s performance:

Eliminate render-blocking resources, the most popular warning in Google Pagespeed Insight can be fixed by generating critical CSS.

critical css generator

When a browser encounters a CSS stylesheet in HTML files, it typically blocks the rendering process. Not all CSS stylesheets are needed in the viewport. That’s why it’s crucial to generate critical CSS for your web page to boost PageSpeed.

But, how to create Cricial CSS to speed up your website?

Don’t worry! RabbitLoader automatically grabs the required CSS to visualize the view-port content and inlines it. By creating critical CSS files for every web page, RabbitLoader optimizes the CSS stylesheet size with a 98% improvement. 

As a result, you can achieve a good Google PageSpeed Insights score. Without generating critical CSS, you can’t achieve a 90+ pageSpeed score.

CSS Optimization, pagespeed insights

In the above picture, you can see that RabbitLoader optimizes an original CSS file (2.35 MB) into just 35.03 KB by generating critical CSS, indicating it reduces the CSS File’s size by 98 %.

  1. Deferring JavaScript can improve the performance metrics:  

Though JavaScript plays a crucial role on a website, it is not the critical piece in the first place, especially when we are talking about page loading speed.  

<!DOCTYPE html>  
<script src = "myscript.js" defer>  
<h1> </h1>  
<h3> This is an example of defer attribute.  </h3>  

RabbitLoader uses the defer attribute to indicate your script will only execute after rendering the Web page. Deferring JavaScript can improve FID, TBT, and TTI metrics.

So, your website’s pagespeed will automatically improve.

Check Also: PageSpeed Optimization Services

  1. Use Content Delivery Network (CDN) to Reduce Network Latency:

A physical distance between a user and the origin server can be the reason for latency. RabbitLoader’s integrated Content Delivery Network (CDN) reduces this distance by distributing static content across the edge servers worldwide. So, the page loading time will automatically decrease.

Without CDN

Without CDN

With CDN



1. What are Render-Blocking Resources?

Render-blocking resources are stylesheets, scripts, and HTML files that block the browser from rendering the web pages’s content above the fold. These resources affect the report of core web vitals assessment


If your website’s Google PageSpeed Insights score is poor, you need to improve this score by speeding up the website for a better user experience as well as SEO rankings. Here, we have suggested the most powerful strategies to reduce the loading time.

If you are not from a coding background, you must use some page speed optimization plugins to achieve a good PSI score. Also, it’s important to keep in mind that using too many plugins can reduce the page load time.

The solution is here. When you are using RabbitLoader, no other optimization tools are required to boost the pagespeed insights data.

WP Rocket vs RabbitLoader: Which Plugin Would Improve Your PageSpeed Score Better ?

WP Rocket is the most popular cache plugin in the WordPress ecosystem. Since 2013, WP Rocket has been leading the optimization scene for wordpress websites. But how does it compare to RabbitLoader?

Here, we will see a detailed comparison between WP Rocket and RabbitLoader, explore the usability of both optimization plugins, and compare the pagespeed scores after installing the plugins individually on the same website. 


We would test both the plugins on one by one & see which plugins helps the website reach a higher pagespeed score in the pagespeed insight test.

WP Rocket vs RabbitLoader: in short

WP Rocket is a premium cache plugin to optimize your wordpress website for better pagespeed performance. With close to 4 million websites using the plugin as claimed by WP Media, it is the leading cache plugin by some distance. 

Over the years Wp cache has moved from just being a cache plugin & have introduced other optimization features too, namely minification, preloading & a few more features to make it more than just a cache plugin.

But when you are using WP Rocket, one would still need to install Imagify for image optimization. If you feel the need for a CDN service you need the premium RocketCDN. And for lazy loading, you need Rocket lazy loading.

In comparison, RabbitLoader is an all-in-one optimization plugin, you would not need any other optimization plugins to improve the performance of your wordpress or woocommerce website.

What is WP Rocket

WP Rocket is a premium wordpress cache plugin. The goal of this plugin is to speed up your website, which is necessary to improve the user experience as well as SEO rankings.

wp rocket

Other than the cache, WP Rocket also uses various optimization techniques like caching, minification of CSS stylesheets, JavaScript files, among others. Wp Rocket being a premium plugin you would have to shell out money even if you wish to try it on your website to gauge your needs.

What is RabbitLoader

RabbitLoader is an all-in-one pagespeed optimization plugin that uses a premium Content Delivery Network (CDN), caching, image optimization, lazy loading, and other techniques to reduce web page loading time for your WordPress website.


When you are using our RabbitLoader, you don’t need to use different plugins for caching,Image optimization, CDN or even minification. Everything that’s needed to optimize your website is done by RabbitLoader itself without you having to toggle through 10 different settings.

Another advantage of RabbitLoader over WP Rocket is the availability of a forever free version. So if your website is not yet receiving a lot of traffic, you can just use RabbitLoader for free and spend the money to get more traffic.

Major Differences Between WP Rocket and RabbitLoader

Now you have a basic idea about WP Rocket and RabbitLoader. Lets see the differences between WP Rocket and RabbitLoader. Here we are mentioning some key differences between these two plugins.

WP RocketRabbitLoader
Image OptimizationTo optimize images, you need to activate the Imagify & yes, you have to pay for it separately too as the free version only allows 200 MB per month.RabbitLoaderOptimizes your images in WebP & AVIF formats using lossless technology. 
CDNSimilar to images you need another plugin, known as RocketCDN. As you guessed it, it is  a premium CDN.RabbitLoader uses integrated CDN with over 300 PoPs.
Premium CDN ChargeAn additional $7.99/ Month for using the premium CDN.No additional charges.
Critical CSSWP Rocket does not generate critical CSS for your pages.RabbitLoader Generates Critical CSS for all your pages, making them load much faster. 
Free versionWP Rocket doesn’t have any free or trail plan.RabbitLoader has a forever free plan  with 5,000 monthly page views.
PlatformsWP Rocket is exclusive to WordPress.RabbitLoader is available for WordPress as well as Shopify, PHP, and Laravel websites.
PricingWP Rocket’s pricing starts from $59/year.Imagify is $99/year. Rocket CDN is an additional  $89/Year

In Total you need to pay $250/ year to optimize your website’s Performance.
Starting from $191/annual. 

When you are using RabbitLoader, no other plugins are required. So, there is no additional charge required to optimize your website pagespeed.

What are the Similarities Between WP Rocket and RabbitLoader

Performance Optimizer: 

Both optimization plugins, WP Rocket, and RabbitLoader can improve Core Web Vitals, address Google pagespeed Insights suggestions, and help you to achieve good pagespeed performance scores. Although the pagespeed score you can reach using these plugins would be different for each of them.

Browser Caching:

Caching can store static files like HTML files, CSS stylesheets, JavaScript files, media files, and images. It minimizes the work for the server, the server wouldn’t have to serve that content over and over and serve the web page for the users if you leverage browser caching.

For example, when you are visiting our website, your browser will download the RabbitLoader logo in the cache. The next time you visit, this logo is directly loaded from the cache. This is how you can save data per web page.

  • WP Rocket and RabbitLoader, both can improve your website speed by generating HTML files so that in the future, users can access them quickly. It also stores static resources like CSS stylesheets, JavaScript, and image files in the user device’s local memory.

Premium CDN: 

A Content Delivery Network (CDN) is a network of interconnected servers that help to speed up a website’s loading time. It reduces the physical distance between the server and the user and proves the latency.

  • Although there is a free CDNs present in WP Rocket, its effect on the latency is next to none as it has very few PoPs.

For a better experience, WP Rocket has a custom with more PoPs. Known as RocketCDN, It offers unlimited bandwidth.

  • RabbitLoader has an integrated Content Delivery Network (CDN) with 300+ edge locations.CDN cache can save the version of your wordpress website and load this when the same user visits it. The CDN also saves the hosting resources.

WP Rocket vs RabbitLoader: Performance Comparison

We can make all the comparisons we want but as they say the proof is in the pussing, so let’s see how WP Rocket fares against RabbitLoader, to find out we would analyze a demo woocommerce website in three different cases.

Once without any optimization plugin, then after installing WP Rocket & finally we would be testing it with RabbitLoader installed. 

Also, we will attach the video of the test along with the screenshots of the results.

Case 1- Checking website’s pagespeed without using any performance optimization plugins.

Let’s check the pagespeed performance score of without plugging any performance optimization tools. 

As expected it didn’t do very well in the pageSpeed test and you managed to achieve a measly 36 for the mobile version and 50 for the desktop version.

Mobile Mode:

In mobile mode, the performance score is just 36. Which indicates this website fails the performance test for the mobile version. Which is not a good sign for any website, specially keeping the mobile first policy google in mind. 

Below are the pagespeed metrics which had a heavy impact on the website’s low pagespeed scores.

Without any plugin Mobile

Desktop mode:

While the desktop division of the The pagespeed performance score is also not very high either, it looks far better than the mobile version. 

Below are the pagespeed metrics that had the biggest impact on its pagespeed score.

  • First Contentful Paint (FCP) – 1.9s
  • Large Contentful Paint (LCP) -2.4s
  • Total Blocking Time (TBT) – 650 ms

Case 2- Let’s check the website’s pagespeed after installing WP Rocket

While installing Wp Rocket is like any other plugin in the wordpress ecosystem, you would need to “configure” it, go to each other individually & activate them.While it might give the user some satisfaction of them doing the optimization, it is nonetheless a time-consuming process.

But what’s the impact of WP Rocket on the pagespeed score?

            Mobile mode:

Well as far as the mobile version goes, it’s next to no improvement, not only that we can see the Total block time is surprisingly increased after using WP Rocket plugin. Not the best way to spend you 60 odd dollars.

with wp rocket

Desktop mode:

However, we do see the value of the WP Rocket in the desktop version of the website. The optimized version of the website managed to achieve a respectable 78 on the pagespeed score.

We can see FCP, LCP & TBT all improving from their previous states to a somewhat respectable score.


See the test video :

Case 3 – Checking the website’s pagespeed after installing RabbitLoader

Finally we would install RabbitLoader after uninstalling WP Rocket of course, & check the performance of, The website is checked within just 5 minutes of installing the plugin and here are the results.

Mobile mode:

Here, after installing RabbitLoader the mobile pagespeed score has improved drastically, while WP Rockets improved the score from 36 for the optimized version to just 37 RabbitLoader manages to bump up the pagespeed scores to a very respectable 82. 

The score improvement is the pagespeed test is the result of improvements made in,

  • FCP ( From to 5.0 seconds to just 3.3 second)
  • LCP ( From to 5.8 seconds to 3.6 seconds) and
  • TBT ( From 1440ms to 40 ms)

Desktop mode:

Finally, for the desktop version, WP Rocket achieved a respectable 78 from the original score of just 50. RabbitLoader archived a near perfect 99 out of 100. So how did RabbitLoader achieve such an unrealistic looking, near perfect score? That too for the home page?

RabbitLoader has reduced the FCP from 1.9 seconds to just 0.6 seconds.While LCP came down from 2.4 seconds to just 0.7 seconds and the TBT became just 10 ms from 650 ms on the unoptimised website.

with rabbitloader

See the test video:

Checking the website’s pagespeed score table view: without any plugin, with WP Rocket, and with RabbitLoader plugin

Without Any PluginWith WP RocketWith RabbitLoader
Mobile PageSpeed Score363782
Desktop PageSpeed Score507899


If you are planning to optimize your website or improve the current optimization, now you have the information on your side to make a judgment call. 

If you have enough time on your hands maybe spend a day installing both WP Rocket & RabbitLoader on your website & see the differences in score yourself.

Maybe you are using WP Rocket for a long time, maybe it’s time you try RabbitLoader which can give you a bit more performance, that little bit of an edge that might become a deciding factor for the search engine to rank you higher or  lower than your competition.


1. Can I use Cloudflare caching with a WP Rocket?

Yes, you can use Cloudflare with WP Rocket & RabbitLoader both  to enhance your website’s security. Both are compatible with Cloudflare.

2. Which plugin provides superior mobile optimization: WP Rocket or RabbitLoader?

Both WP Rocket & RabbitLoader optimize your website’s mobile optimization. We check the pagespeed performance on a live website and posted the results here for your to interpret the results.

3. What are the key benefits of using WP Rocket for website performance?

WP Rocket is a popular WordPress plugin that is used to optimize performance your wordpress or woocommerce website by implementing various techniques such as browser caching, minifying HTML, CSS, and JavaScript files, using premium CDN (RocketCDN), and many more.

What Is First Contentful Paint And How To Optimize It To Pass Core Web Vitals?

Google released First Contentful Paint (FCP) to assess a web page’s initial loading time. To improve your website’s FCP performance, you can either implement optimization strategies like using browser & CDN caching, reducing the HTML, CSS, and JavaScript file size, and removing the unused CSS, or you can install the RabbitLoader performance optimization tool on your website if you are looking for an effortless solution.

First contentful paint

Although First Contentful Paint is not a core web vitals metric, if you need to improve your user experience and pass the Core Web Vitals, you can’t neglect FCP. 

Let’s discuss what you need to know about FCP and explore helpful strategies for optimizing it to pass the Core Web Vitals and boost your Google PageSpeed Insights score of your website. 

What Is the First Contentful Paint?

First Contentful Paint quantifies the time from when a user visits a web page to when the web page’s first content is displayed on the browser. This content can include any images (including the logo and background images), text, any <svg> elements, or non-white canvas.

FCP Matix

FCP is a crucial metric for your user experience & PageSpeed score. When visiting a web page for the first time, if users spot a blank page, they might get confused about whether the website is loading or not. They will likely leave the page or frantically try to reload it.

Difference Between LCP & FCP

As a competent web developer or website owner, it’s essential to understand how the First Contentful Paint (FCP) differs from the Largest Contentful Paint (LCP).    


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Where First Contentful Paint is used to measure the time it requires to display a web page’s first piece of content, Largest Contentful Paint calculates the time it takes to display the largest element of a web page. This largest element can be a hero image or a text block. 

What Is A Good FCP Time?

According to Google, a website’s FCP time needs to be less than 1.8 seconds to pass the core web vitals assessment. If the FCP score is between 1.8 seconds and 3.0 seconds, Google PageSpeed Insights suggests improving the FCP performance to provide a better user experience.

First contentful paint- FCP

Finally, if the FCP time exceeds 3.0 seconds, your website fails the core web vitals test. To be in a green zone, you need to optimize your FCP time to pass the PageSpeed test.   

The Importance Of Optimizing FCP

Before diving into the solution, let’s explore the importance of optimizing FCP performance. 

  • Lower Bounce Rate = Better User Experience

By optimizing your website’s FCP performance, you can significantly increase your user experience. Since FCP makes the first impression on your website, users would be more likely to engage with a well-functioning website. Which results in a lower bounce rate. 

  • Improve The Conversion Rate

The conversion rate determines the percentage of visitors who can successfully finish an action on your website and become a lead or a buyer.  A lower bounce rate is much more likely to increase your conversion rate by engaging the visitors with the website’s content.  

  • Better Organic Rankings

Google always prioritizes the user experience. Therefore, optimizing your FCP time can significantly improve your PageSpeed score which is a strong positive signal for your Google organic rankings.

The Most Common Reasons For Poor FCP Performance 

While several factors can negatively impact the First Contentful Paint (FCP). Let’s focus on the most common reasons for poor FCP performance.   

  • A slow initial server response time

  • Render-blocking JavaScript and CSS files

  • Unused CSS

  • An excessive DOM size 

  • An unoptimized image

How To Optimize Your Website’s FCP?

Let’s explore the optimization techniques to mitigate each of the above mentioned issues that are impacting the FCP to improve the First Contentful Paint time of your website. 

Use Browser & CDN Caching

Using a browser and CDN caching mechanism can significantly reduce the initial server response time and improve the Time to First Byte (TTFB) performance. 

However, adding a browser cache is not enough for web optimization; you need to set efficient caching policies to provide a better user experience and to make sure you are not serving stale content to your visitors.

Manually implementing the browser cache with an efficient caching policy requires extensive technical knowledge. Read our server static assets with an efficient cache policy blog if you wish to explore more on how to do it yourself.  

If you do not wish to go into the nitty gritty of it & just need the issue to be solved, you can install a performance optimization tool like RabbitLoader to implement the browser cache with an efficient caching policy

RabbitLoader also distributes the cacheable content between 300+ edge servers worldwide to reduce the latency.

Reduce The HTML, CSS, And JavaScript File Size

When it comes to FCP optimization, reducing HTML, CSS, and JavaScript file size is one of the most effective strategies to improve the FCP time. There are two ways to reduce these resources’ file size: minification & compression. 

While minification removes unnecessary comments, line breaks, and white space from the resource files, by compressing the method, you can reduce the redundancy of the string variable in the HTML, CSS, and JavaScript files. 

When you use RabbitLoader, you don’t need to put any extra effort into the minification and compression process, RabbitLoader takes care of it.

Reduce unused CSS

The term Unused CSS indicates CSS rules that are not utilized in the current web page design but consume space in your CSS stylesheets. This unused CSS would unnecessarily increase your website’s page size.

Reduce Unused CSS

By removing this unused CSS, you can improve the core web vitals performance, especially the FCP and LCP performance. If you want to remove the unused CSS manually without having proper coding knowledge, it can be risky. One mistake can harm the whole web page’s design.

Therefore, using RabbitLoader would be the safest option if you are not versed in CSS  

Optimize Your First Contentful Paint With RabbitLoader

Web optimization requires a lot of effort and technical knowledge. Thus, many web developers end up using a lot of different WordPress plugins to improve PageSpeed performance. However, using ten different plugins usually harms PageSpeed performance as these plugins conflict with each other.

When you use RabbitLoader, it will implement all the optimization techniques needed to pass the core web vitals and improve your PageSpeed score. Therefore, you don’t need to use other performance optimization plugins, avoiding plugin conflicts and improving PageSpeed performance. 

If you want to seriously improve your website’s PageSpeed performance to provide a seamless user experience, you must install RabbitLoader to improve the First Contentful Paint performance along with the other performance metrics and boost your PageSpeed performance.    


Get The Best PageSpeed Score

For Your WordPress Website

All in One Optimization Plugin
No Coding Knowledge Required