See how to configure the settings and purge cache in WP Fastest Cache. It was a winner in my recent Top WordPress Caching Plugins Head-to-Head Tests and is free and easy to use.
NOTE – WP Fastest Cache continues to make improvements, and I’m always learning, so I’m constantly updating this post.
Covered in this tutorial:
- Following are screenshots of all the settings in both the free and paid versions.
- Below the screenshot are more details for settings that have options or more clarification, if needed.
- Plus, near the end, you’ll see how to purge the plugin’s cache.
- At the very end you’ll see my best practices for testing the settings.
NOTE: Be sure to scroll to the end of the plugin’s settings and click the Submit button to save your changes.
NOTE: If you run MediaVine ads, you will need to hard code the CSP to block non-HTTPS ads from running on your site in your .htaccess file instead of the Insecure Assets setting in the MediaVine plugin. Contact me for help with this. It’s an easy and quick thing to do. And is way better than using some of the other caching plugins they recommend if you’re serious about speed and stability with your site!
NOTE: If you use iframes to embed Amazon affiliate links, you will need to exclude them if you use lazy load for images. See the Lazy Load settings section for details. Do not exclude iframes entirely! That’s an all-or-nothing setting and will knock out any help you could get with speeding up videos that are embedded using iframe too. Just exclude the Amazon links using one, global setting for them.
Caching is tricky business and must be configured to match your site, host server type, and CDN.
Please read this entire tutorial. Don’t just click stuff based on the screen shots.
You wouldn’t believe how many site audits I do where folks install plugins and never configure them, or even turn them on!
You actually get a whale of a lot in caching help just by clicking Enable on this plugin.
Preload compiles all PHP (code) and SQL (database) calls into a static HTML file for faster delivery.
Preload use rule of thumb:
- Do not use if you are also using Cloudflare.
- If not using Cloudflare:
- Less than 10k hits/day, turn on preload.
- More than 10k hits/day, don’t turn on preload.
You might want to monitor your hosting resources, or check with your CDN provider if you are using one other than Cloudflare.
If you do use preload, only turn on the items that get visited the most, like:
This will save on your hosting resources too.
If you need to turn on others, do so, just keep an eye on your hosting resource load.
Logged In Users
WP Fastest Cache already sets a logged in user cookie for:
- Admin User
- Woocommerce User
- Commenter (when comment is held in moderation)
Subscribers, such as on a member site would also be considered logged in Users. And you want them to see the cached version of the site’s content.
So, you want to leave this setting unchecked.
(FYI, I verified all of the above with the plugin dev. I also suggested he create documentation to clarify what counts as a logged in user.)
Because mobile shows less content than desktop, there are different combinations you need to consider for these settings.
If you are using the premium version of WPFC and have lazy load turned on, then turn on both mobile settings too.
If you are using the free version of WPFC and have a responsive theme, then turn off both mobile settings.
If you have a totally separate mobile version of your site, such as AMP, then turn on both mobile settings. (The second setting is only available in the premium version of this plugin.)
Clear all Cache for the whole site is the default setting when you publish a new post. You’ll likely want to leave it set this way due to how many places your new post may display on your site, such as any type of recent post listing.
NOTE: If you notice the cache not updating properly everywhere when you add a new post, then set this to Clear All Cache
When you update an existing post, only select site elements are affected, so I recommend setting the plugin to only clear cache on them, instead of losing speed on the rest of the site.
Minify and Combine
READ this whole section before turning these elements on!!!
Minification and combining static elements can definitely speed up your site.
They can both definitely break some sites, or site functions too!!!
If you choose to use any of these settings, see the end of this post for testing best practices.
There are two common places to set minification – via a local caching plugin and via a CDN like Cloudflare.
The dev suggests you do one or the other, not both.
However, my tests, and documentation from Cloudflare, suggest that you should do both. That’s the way I have my sites, and my site audit clients set, and we’re good.
The minification in most all plugins is more aggressive than Cloudflare and will generally render better speed.
The free version of WP Fastest Cache has less aggressive settings than the paid version.
The more aggressive settings are grayed out on the free version.
Combining CSS and JS will not yield as much speed improvement on HTTPS sites as it will for non-HTTPS sites. That’s because HTTPS takes advantage of the HTTP/2 protocol, which delivers more elements in parallel by default. As HTTP/2 improves, combining CSS and JS will become less necessary to improve speed. But we aren’t there yet.
Combining also carries the greatest risk of breaking site elements, due to so many plugins having CSS and JS elements, besides those found in just the theme. Files that don’t play well with this setting can be excluded from the combo.
So, while combining works, it may take more tweaking and testing to get it to work well on your site.
Contact me if you need help with these settings.
This type of compression makes a zip version of your site elements, which the browser later explodes. It delivers up to 85% speed improvement.
But, it only works completely on Apache servers.
If you’re on Litespeed, it already has a similar function built in, called APC, which will show up in speed test results as Gzip. Adding Gzip via this plugin will speed up the elements that APC can’t do alone. Just don’t expect as drastic a speed improvement as on Apache, simply because it needs more speed help.
If you’re using Cloudflare, it uses Brotli compression, which is even better than Gzip, but not all browsers support it fully yet. Brotli will also display positive for Gzip in speed tests.
Gzip Use Rule of Thumb:
- Turn on for Apache servers
- Turn on for Litespeed Servers and test again for modest additional speed improvements
- Turn on even if you are using Brotli via Cloudflare
This setting needs to coordinate with your CDN, like Cloudflare, if you are using that.
Turn this on in the WPFC plugin.
Then at CloudFlare, set Browser Caching to Respect Existing Headers.
You may need to run tests to ensure this combo is the one that works best for your setup.
The dev sets browser caching in the plugin for 6 months. And to ensure that it and Cloudflare stay in step with each other, you MUST set the CDN to respect the headers that this plugin is sending, instead of setting a time frame at the CDN too.
Contact me if you need help with your settings combo.
NOTE: You will see a pop up notice that you should integrate this plugin with Cloudflare. I disagree with the settings the dev uses in that integration. Use the settings I suggest instead, as I have the test results as well as documentation from Clouflare to prove mine work better. These have been shared with the dev too, and if he changes them, I’ll update this post.
Definitely turn this on if you don’t use emojis in your content or comments. You’ll get a small speed improvement all over your site.
Render Blocking JS
This setting could significantly speed up your site. But, like all JS related settings, it could also break your site.
Definitely give it a try.
This setting will speed up most sites, as it pushes the calls outside your site to Google way down in the load order.
However, it could also reduce your Google PageSpeed Insight (GPSI) score, depending on how much has to load prior to the Google fonts loading. GPSI wants to ensure that your theme displays default fonts quickly until the Google fonts load.
Lazy loading works on images to provide a smaller placeholder image instead of the actual image, on any images that are below the fold on the device being used by the visitor. This allows Google to index the image attributes without slowing your page load down.
The actual image is loaded once the site visitor scrolls to that section of the post/page.
Lazy Load also works on videos when iframe code is used to embed them, and when the video appears below the fold. It will not work on videos using oEmbed.
You can also select your own placeholder image instead of the one provided by WPFC, but it is sufficient.
FYI: there is no option to turn off lazy load on a per page/post basis. But, when you click the Next button, you will see another screen to Exclude Sources.
These will be applied globally, though.
FYI: If you already have lazy load turned on and want to check your settings, then uncheck the box for lazy load and then check it again and the following settings screens will appear.
Ensure Exclude full size images in posts or pages is unchecked.
If you are using iframes for Amazon affiliate links, you will need to exclude them here.
In the Add Keyword field, input this: ws-na.amazon-adsystem.com and hit Enter. Then click the Finish button.
If you are using iFrames for video ads, such as from Mediavine, you will need to exclude all iFrames here.
In the Add Keyword field, type in iframe and hit Enter. Then click the Finish button.
If you turn on Lazy Load, be sure to turn on the Mobile settings too!! See those settings near the top of this tutorial.
Save Your Settings
Be sure to click the blue Submit button at the bottom.
You should get a green bar notification at the top that your settings have been saved.
Purge or Delete Cache
There are 3 easy ways to delete/purge the plugin’s cache.
There is a Clear Cache tool in your admin toolbar.
Or, you can go to the plugin’s settings and purge there.
- Click the Delete Cache tab at the top.
- And then click the blue Delete Cache button.
If you turned on minification and/or combine, then you will also need to delete both caches (both buttons shown below) when you make a css or style change to your theme, or one of your plugins that has a style sheet updates.
I only use the Cloudflare CDN as I believe it gives superior security and performance.
However, I like my custom settings better than what are suggested by this plugin – so I don’t use the integration feature.
You may also see a pop up to suggest you do the integration. I simply turn it off.
I also prefer to run the Cloudflare plugin, and you can’t have it and this integration setup at the same time.
If you do use this integration it has a setup wizard that will make the following changes at Cloudflare:
- turn off the Auto Minify
- turn off Rocket Loader – if you were using it
- set the Browser Cache Expiration to 6 months
I disagree with the dev about this settings and have the test data and documentation from Cloudflare to prove my settings work better. These findings have been sent to the dev and if he updates the plugin, I’ll update this post.
WP Fastest Cache does have a premium version available. You have to download and install the free version first, and then you can upgrade from within it. There is a one-time payment per site.
For ultimate speed, it is definitely worth paying for!!
The minify and combine features are far more aggressive in the paid version and there are other features to help with database cleaning and reduction of calls to your database.
How to Test Your Settings
Take an accurate speed test before you start.
Following is the method I use to test these plugin settings.
- Max out the settings in the free version.
- Purge all cache everywhere.
- Check the site function and speed immediately, then after 10 hours or next day.
- If all is well, max out the settings in the paid version.
- Repeat the purge and checks.
If your site slows down, it’s likely that your theme can’t handle some of the combine settings.
- Turn off the combine for CSS and JS and recheck.
- Turn back on the CSS combine and recheck.
- Turn off the CSS combine and turn on the JS combine and recheck.
This should give you an idea of which one is the culprit and you may have to leave that extra speed tweak off until you change themes or plugins, whichever is the cause.
Want Even Better Speed?
My site audits go deep and reveal the real drags on your site, plus performance holes that are letting bots eat up all of your system resources, making the site slow too.
Want to learn how to do site audits?
My Webmaster Training teaches designers and technical VAs how to set up sites securely, convert them to HTTPS, and make them fast.