How to Configure WP Fastest Cache to fix Core Web Vitals Errors in 2021

Loading speed is a relevant factor to improve the positioning of a web page, and of course, as per Google’s Core Web Vitals update is one of the ranking factors. The loading time not only influences that the search engine spiders can crawl the content more quickly, but also that the users can access the content more quickly.

Then? What are you waiting for to reduce the loading time of your WordPress? You should try Configure WP Fastest Cache in your WordPress right away.

From Mageplaza they tell us that if we reduce the loading time by 1 second, we can obtain a 27% increase in conversion. Can you imagine what impact this can have on e-commerce like Amazon? The same happens with our WordPress, or in our WordPress + WooCommerce online store. Having a cache is essential.

Before configuring WP Fastest cache plugin, let’s check website speed first:

So you can see Website Speed is not good and the website has many Core Web Vitals errors. So let’s configure WP Fastest Cache and see the results below.

WP Fastest Cache Configuration

Although we have activated WP Fastest Cache on our website, the cache and the options included in this plugin are not yet active. We have a couple more steps to take to get it fully configured.

I’m going to show you how I have it:

In the tab to configure WP Fastest Cache, you will see a series of checkboxes that you will have to activate. Don’t you know what one of them is for? Now I tell you.


The first tab is Settings. Enable the following options:

  • Cache system: Enable. activate the plugin cache in WordPress. It is interesting that you assign certain rules in addition to this, such as clearing the cache when we publish or update a post.
  • Preload: Enable. WordPress cache is done on demand. When a user accesses a section of our website, it is cached so that future consultations are faster. Activate the preload option if you want to cache the entire web automatically.
  • Logged-in Users: it is recommended to enable it. If you are logged in, you will not see the cached copy of your WordPress. This is very useful when we make changes since we can see them in real-time, instead of the cached copy.
  • Mobile: Enable. WP Fastest Cache creates a different cache for the mobile version since the responsive pages change depending on the resolution of the device from where we access it. Activate this option to only load the mobile cache on mobiles, and not the desktop cache.
  • New post: Enable. clears the cache when a new post is published. You can clear the entire cache, or just the homepage, categories, and tags (recommended).
  • Update Post: Enable. clears the cache when a post is updated. Here you can clear the entire cache if you consider it, especially if you dynamically change the related content.
  • Minify HTML: Enable. compress the HTML by removing white space and comments. The smaller the size of the HTML, the less time it will take for the visitor to download the content.
  • Minify CSS: Enable. reduces the size of CSS by eliminating spaces and useless comments.
  • Combine CSS: Enable. CSS is the style sheets that shape your WordPress. In principle, there should be no problem in combining them into a single file. And it is ideal, since this way we reduce the number of requests to the server.
  • Minify Js: reduce the size of the Js eliminating spaces and useless comments.
  • Combine Js: Enable. Javascript is a programming language. The “Js files” are source codes that “do things on the web.” In a very rough way. Combining them into a single file can cause display problems in the template, or cause some functions to stop working. This is because, like most source codes, it requires that they be loaded in an orderly manner. Why does it not make sense for a JS to call another that has not yet been executed? 
  • GZIP: Enable. GZIP is an algorithm that compresses your WordPress files and sends them to the user who requests them with a reduced size. This reduces the loading speed.
  • Browser caching: Enable. activating this option will set a cache time for your WordPress resources. Does it make sense that if I access several pages on the same website, I have to download all the content? Indeed, no. This option sets a maximum time for which files will remain in your visitor’s browser (if possible). It will speed up your web browsing.

Cache validity time

We can configure WP Fastest Cache to clear the cache of certain pages frequently. This is very useful for sections with very dynamic content, such as the home page or blog.

Access “Cache Validity” and in “Timeout Rules” select “Add New Rule”.

In “If REQUEST-URI” select between the options:

  • All: all URIs.
  • Homepage: the main page
  • Stars with: all URIs that start with a given string.
  • Is equal to exactly equal to a specific URI.

Go to the “Then” drop-down and select the interval in which you want the cache to be cleared in that section or sections.

Exclude Pages or Posts from the Cache

We can also exclude certain sections, User-Agents, Cookies, JS, or CSS from the WP Fastest cache for some reason, although hey, it is a less usual case.

As you can see in the screenshot above, we can exclude certain URLs, such as wp-login, wp-admin, or any other section of the web by adding a new rule.

In the same way, we can exclude a User-agent so that it does not see the cache copy, but the non-cached version. I can’t think of a reason for this, but it might come in handy if you’re having trouble with the Googlebot or any other spider.

Finally, we can exclude some CSS and JS from the cache if they cause us problems. If you know what you do and perfectly control the CSS and JS that are loaded in your WordPress, it is a good option to solve display problems or problems in the template’s functionalities.

Common Issues when activating WP Fastest Cache?

It happens that after installing WP Fastest Cache, the WordPress template crashes or stops displaying correctly. Many premium themes have already planned this point and have been made compatible with these plugins, but others could have bugs.

These are some of the most frequent failures when configuring WP Fastest Cache:

  • The page looks bad or misplaced: try disabling minification and/or a combination of CSS.
  • I don’t get theme updates: disable CSS minification. In rare cases, minification removes the header from style.css, which contains various vital template data.
  • Some template features don’t work: try disabling JS minification and/or merge. As I said before, WP Fastest Cache does not know the order of execution of the JS, and it can be interesting.

How to Clear Cache in WP Fastest Cache

In addition to knowing how to configure WP Fastest Cache, it is also very useful to know how to clear the cache. If we develop the web and make changes to the CSS or JS, this is very important.

There are two ways to clear the WP Fastest Cache cache:

  • Option 1: From the upper administration bar, press WPFC, and “Delete Cache” or “Delete Cache and Minified CSS / JS”.
  • Option 2: From the sidebar. Press “WP Fastest Cache”, “Clear the cache”, and then select between the options: “Clear the Cache” or “Delete Cache and Minified CSS / JS”.

Result Matters – Conclusion

Now that you know how to configure WP Fastest Cache to fix Core Web Vitals errors, all you have to do is speed up your web page to the maximum so that your visitors access the content at the click of a button.

Let’s check the result:

page speed result after Litespeed plugin configuration

Do you have questions about how to configure WP Fastest Cache in WordPress? Leave us a comment and we will be happy to help you.

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