Sooner or later, every WordPress website reaches its performance limits. As is well known, WordPress is a dynamic system for generating HTML (CMS). This means that with every call, various scripts are loaded in the background on the server and sent through the PHP interpreter. Thereby thousands of calculations are performed and also data from the database is loaded. Finally, the result is “assembled” and returned to the browser.
Depending on the server hardware, hosting situation, number of plugins or amount of page content, this process can take several seconds. If the visitor has a slow connection, the “time to display the page” may be 5 seconds or longer. This is unacceptable because it will cause these visitors to go to another website. If the waiting time is significantly longer than 1 to 3 seconds, the visitor will have the feeling that the website is currently unavailable.
Fortunately, there are a number of so-called caching plugins for WordPress that can solve exactly this problem. They all have in common that they are complicated to set. They also have to be configured first and then activated. Not so WP Rocket: It is activated directly after installation and speeds up loading times enormously. Furthermore, it can be further optimized in various areas.
In this article we summarize once again all the important information about the installation and operation or optimization of WP Rocket.
The features: What does WP Rocket have to offer?
First, WP Rocket has a large user base. With more than 1 million users worldwide, the software is used by a large number of WordPress users. This gives you the assurance that the plugin will continue to be worked on in the future and that errors will be detected and fixed quickly. The ratings in the network are therefore not without reason above average.
In addition to the standard page caching functionality, WP Rocket can also pre-cache the entire cache of the website, (pre)compress static files, images are only loaded when the visitor scrolls to the appropriate position on the page (lazy loading) and developer support is also visible. So it is exciting to have a look at the plugin in detail.
Instructions: Installation and ready?
After a standard installation under WordPress version 5.4, WP Rocket is ready to use, i.e. posts and pages are cached without further configuration. The loading times on the website are directly accelerated.
But there is even more. The best way to demonstrate the power of WP Rocket is to simply go from menu item to menu item through the backend. For testing purposes, we have created a whole series of sample pages and articles in WordPress.
These sample pages have different layout elements and images. Here in the landscape view (a long screenshot cut and displayed side by side).
The dashboard of WP Rocket
Directly after the installation you landed in the dashboard. Here you get an overview of the most important information, and also the possibility to empty or fill the cache. If you want, you can also participate in the beta test program.
The cache in WP Rocket
In the Cache area, you can activate the cache for mobile devices. A separate cache for mobile devices may then be necessary if the theme you are using is not yet responsive and generates its own layout for mobile devices. Caching can also be activated for logged on WordPress users. However, this is generally not recommended. A better solution is to open another browser window in incognito mode to check if the caching actually works. In the video we have also checked this.
Under Cache duration you can set the time until the cache is invalidated. As shown in the screenshot, in this case the cache is rebuilt after 10 hours.
File optimization with WP Rocket
This section offers a wide range of options. First of all, the HTML can be minified. The HTML code is reduced as much as possible. Unnecessary spaces, blank lines and comments have to go.
The use of Google fonts can slow down the loading time. Especially if more than one font is used. Here the plugin rewrites the code so that only one request is sent to the Google servers. The plugin also appends the parameter display=swap to the request. Last but not least the attribute rel=preconnect is added.
When loading static resources, developers like to append query strings to the file. This looks for example like this: style.css?ver=1.0. WP Rocket then rewrites the file name to another format: style-1-0.css. This is clever, because this way you can categorically rule out that old layout statements are loaded.
In addition to HTML, CSS and JS files can also be minified, merged and optimized. As always, the minification removes spaces, blank lines and comments. The summary makes many different files into one. So the browser only has to load one larger file, which is faster.
Both CSS and JS can prevent a page from being displayed as quickly as possible if the implementation is not good. Here it is definitely worth a test to see if this setting actually speeds up the display of the page. Whether this is still perceptible to the naked eye remains to be seen, however. You will probably have to use the tools for this.
“Remove jQuery Migrate” is only needed nowadays if there are many website visitors who still use very old browsers and jQuery is still used. Whether this is the case can be found out by taking a look at your own Google Analytics.
Media optimization with WP Rocket
In the Media section, there are a lot of settings for pictures, videos and other items. Lazy Loading is in principle always recommended. This means that pictures on the page are only loaded when they are scrolled into the visible area. Especially on pages where there are a lot of pictures, like on this page here, this is really worth it. Even more so, on pages with many videos. A page with ten YouTube videos starts to load ten videos at once when you call them up. This is prevented by clicking on “Replace YouTube iFrame with preview image”.
Emojis and embeds should also be disabled by default. If possible, the WordPress installation should also be configured to support Google’s WebP image format. WebP often produces smaller files than JPEG with the same quality.
Let the cache fill
An interesting feature of WP Rocket is the Active Preloading. As soon as the cache expires, it must be replenished. If the Google bot comes along just at this time and wants to crawl all pages at once (or shortly after each other), the website performance may not be optimal. Active Preloading does this in the background. Ideally, a sitemap is stored for the URLs to be crawled. Then Active Preloading becomes proactive and always builds up a fresh cache. The disadvantage: If you make changes often during the day, you always trigger a new, complete caching process. With a few hundred posts maybe no problem yet. With several thousand, however, it is. The application needs to be well thought out.
The DNS prefetch function causes certain URLs to be pre-resolved in the background. The IP address of the URL is determined in advance, which can lead to a small speed boost, especially with mobile network connections. If you want to use this, enter each line of external domains, with a double slash (//) in front. The Google fonts server would be a good example here: //fonts.gstatic.com
Every configuration needs its exceptions. Therefore, you can define in this section in which cases pages should not be cached – for certain URLs, cookies or user agents.
Sometimes there are URLs that create their cache outside WordPress. Then enter these in the “always delete” area.
Normally WP Rocket does not create a cache for URLs with query strings. If it should do so, such parameters can be specified under “Cache for query strings”. There is also an example in the documentation: example.com/page/?country=italy.
Database optimizations with WP Rocket
Please always create a backup before making changes to the database! Afterwards the database can be relieved of various possibly unnecessary entries. However, you should be sure not to delete something you need later. Especially the revisions of the articles and pages could be useful again. We also don’t see a very good possibility to optimize the performance here. Unless there are now thousands of revisions in the database, which have accumulated over months and years. So this feature is more for very active publishing.
Using a CDN (Content Delivery Network)
A Content Delivery Network is originally designed to provide an international network of cached pages so that no matter where a visitor goes to a page, it can always be delivered as quickly as possible. For example, a customer who is currently on vacation in Australia can surf a German website just as quickly without actually being in Germany. If you expect international traffic, you should get some sleep.
However, there are separate add-ons for the popular services of Cloudflare and Sucuri. So please do not configure them on this page.
Set the heartbeat frequency
WordPress uses a protocol called Heartbeat in the background. This protocol communicates continuously with the server to do various tasks, for example to enable automatic saving. Depending on the server capacities, this can lead to a slowdown. Usually, however, only with shared hosting providers where several users share a server instance. It is recommended to try this feature when resources are running low. In other words: If you already have to stop the heartbeat, then consider whether it might not make more sense to change the hosting provider and book a faster server.
Using add-ons for WP Rocket
WP Rocket also comes with several add-ons. It is worthwhile to save the scripts of Google Analytics and the Facebook pixel locally. The Varnish cache is only for specialists or for people who already have Varnish preinstalled on their server.
Free tutorials on WP Rocket
WP Rocket has several highly produced video tutorials (in English) that greatly enhance some of the features and possibilities. These are also available free of charge on the website.
Conclusion: Is WP Rocket right for your WordPress website?
A caching plugin is recommended for any website that plans to increase its traffic. An older or not very well sized server can quickly go downhill if too many users access it at the same time. Correctly adjusted caching can increase the performance of your website hundreds or thousands of times.
After all we have found out about WP Rocket so far, especially in our own tests, we can really recommend this plugin to you. It is easy to configure for a caching plugin, highly efficient, rocket fast and affordable.