The core of WordPress is packed with features, tools, and utilities, many of which help make WordPress the world’s number one content management system.

Most WordPress features are well known, such as custom post types, action and filter hooks, and the visual editor, but some of them are not necessarily as “well known” as others. In this article, we’ll discuss one of WordPress’s lesser-known (but very useful) features: must-use plugins.

What are the necessary plug-ins?

It’s not surprising that the must-use plugin feature is overlooked, since it was introduced in WPMU (WordPress Multi-User), and WPMU wasn’t integrated into WordPress Core until WordPress 3.0. At the time, a folder called mu-plugins provided network administrators with the ability to activate plugins on every blog in the network. After merging in WordPress 3.0, the "mu-plugins" directory remains, with its name (according to the Codex) reinterpreted meaning "must-use plugins".

Main functions of must-use plug-ins

Must-have plug-ins each have their own advantages and disadvantages, let’s take a look:

They are always on: Essentially, must-use plugins are plugins that must be used and automatically loaded in your WordPress website (or web).

You cannot disable them: Even if you are an administrator, you cannot disable or remove plug-ins that must be used. However, you can delete them from the mu-plugins directory (which, by the way, is under wp-content). You can't install new plugins there either - you have to manually upload them to the directory.

They are loaded before normal plugins: mu-plugins Plugins in the directory are loaded before plugins in the plugins directory. Interestingly, the plugins that must be used are loaded in alphabetical order.

You can't use activation/deactivation hooks: This one is self-explanatory - since plugins that must be used are automatically activated and cannot be deactivated or uninstalled, you can't use activate or deactivate for them Use a hook.

They won’t update: mu-plugins Plugins in the directory will not update automatically, and WordPress will not notify you of new versions. This means you mustmanually keep them up to date.

You must use PHP files: WordPress will not look at folders in the mu-plugins directory - you must place PHP files in the root of that directory. No worries, though: you can create a proxy PHP file and then require the main file in the plugins folder.

Ideas on where they could be used

Must-have plugins have many uses, whether they are clever, creative or just to save the world. Let’s take a look at some examples I can think of – if you have an idea, don’t forget to share it with us!

Must-use plug-ins for use on multi-site networks

Multisite networking is the reason the mu-plugins directory exists, so I put this idea above the others.

While it may be a better idea to just use the Network Activation feature, if you need more features, there are must-have plugins. There are various differences between network-activated plugins and plugins that must be used (explained in this very old blog post), some of which may apply to your network.

Must-use plug-ins for use on the client website

If you grant (or must) access a customer's admin account, they may tend to use settings, theme options, plugins, and any other pages they have access to. When they try to deactivate (or worse, remove) certain plugins, they may be tempted to call you on a Saturday night and admit their guilt - or blame you for not maintaining the site.

If you move all plugin folders to the mu-plugins directory and create a PHP file that requires the main files for these plugins, your client will not be able to deactivate these plugins. But be warned: you won't get automatic updates!

Using must-use plugins for site-specific plugins

This is my favorite must-have plugin use.

If your website requires some key functionality, the right thing to do is to create a website-specific plugin. Since you can't tolerate accidental deactivation of a site-specific plugin, you'd better move it to the mu-plugins directory so even you can't disable it. And since you are a developer and you don't use the plugin anywhere else, there won't be any plugin updates.

in conclusion

In this article, I want to introduce you to one of the most underrated (and often unknown) features of WordPress. I was really shocked when I discovered the plugin I had to use, and I hope you are too. We definitely have must-have plugins in more areas than I can think of, but these alone can make a huge difference to your WordPress site.

Do you agree that the necessary plug-ins are useful? Can you think of more use cases for must-have plugins? Leave a comment below and let us know what you think. If you liked this article, don’t forget to share it with your friends!