Cache Plugins compatibility

This is a quick note to everyone using a cache plugin with FVM (which you should be using, unless your hosting already has cache).

Make sure to read the faqs for some other useful information as well:
https://www.ads-software.com/plugins/fast-velocity-minify/faq/

FVM is compatible with all cache plugins, provided that you make some adjustments on the cache plugins settings, to avoid conflicts, double minification and basically, duplicating work for your server.

In other words, you must disable any similar features on the cache plugin / server cache, theme, etc, that do basically the same thing as FVM.

Those are HTML minification, JS merging and minification and CSS merging and minification, so if you see any option similar to this on your cache plugin and you still want to use FVM, you must disable those options.

Note that you will need to purge all caches after making changes. I suggest completely disabling cache on the server, cloudflare, plugins, etc, while you are testing FVM settings, and then enable and purge one last time once you are happy with the results.

Note that your scores can vary drastically not because of the plugin, but due to things like time to first byte. A fraction of a second can shave away 50+ points on pagespeed insights tests, however it will probably be fine once your cache is back again.

What you need to see, is the recommendations for JS/CSS related issues, which FVM is meant to fix. Of course, it still cannot do anything about your ads, facebook pixels, analytics, etc… because those are external libraries that must load straight from their origin, for which you have no control (do not try to merge those).

Back to cache plugins, in the past FVM would purge it’s cache and because some cache plugins are not supported, it would mean that the page cache would be pointing to deleted FVM files.

From a few versions back, FVM started keeping older versions of minified cache files to avoid 404 (not found) references on very long html page caches. That means, this time when you purge FVM cache, or when FVM does it automatically, it increments the file name instead of simply deleting the old cache.

The new cache will be generated as needed, but the old files will stay on the server for another 3 months, until they are deleted by a daily cronjob, which will give you plenty of time for your old cache to expire.

Nevertheless, FVM also tries to purge the cache on most popular cache plugins and some hosting companies.

The full list of “supported” cache plugins is in the description, but copy pasted here for convenience.

The automatic purge is active for the following plugins and hosting:

W3 Total Cache, WP Supercache, WP Rocket, Wp Fastest Cache, Cachify, Comet Cache, Zen Cache, LiteSpeed Cache, Cache Enabler, SG Optimizer, Breeze (Cloudways), Godaddy Managed WordPress Hosting and WP Engine

Note however, that most server providers have a limit of how many times you can purge caches. For example, wpengine, only allows you to purge caches once every 5 minutes, which means, no matter how many times you purge caches on wordpress, they will only do it once every 5 minutes.

Recently, WPFC and WP Rocket started including a notice saying that FVM is not compatible and should be disabled… which makes sense. Nobody wants to admit that a third party (free) plugin does some tasks better than their own product.

I can assure you that as long as you disable their similar functionality (as explained at the beginning of this post) FVM works just fine, however, obviously the owner of those products don’t want you to disable their own features, in favour of another product which is free.

For example, on WP Rocket, you simply need to disable certain features that overlap with FVM (usually everything under the files tab), regardless of what the notice says.
The same is true for WPFC… it works fine, provided you disable the same similar features.

It’s up to you to decide which plugin you want to use for your site, and which functionality you want to use from each plugin.

I still suggest trying all the options from those cache plugins first, because one plugin is usually better than having two. However, in terms or results (which is what it matters), FVM will probably give you better scores because I probably put more effort into this free plugin than their entire team… and also maybe, because I have 10+ years of experience coding for wordpress.

I don’t claim FVM to be the best plugin for minification and merging for ALL sites (it doesn’t work with some themes or plugins at times), but for the majority of sites, and in the right hands (a tech savvy user, a developer, etc) it will probably beat any other free or paid plugin out there.

Whenever you see a notice on your cache plugin, stating about an incompatibility with FVM, simply follow the steps to disable their equivalent features and try it for yourself.

Unless they specifically block it from working together… FVM will work with any cache plugin.

Thanks everyone,

Raul