WordPress – How to create a “Must-Use” plugin (mu-plugins)

A “Must-Use” plugin is like an ordinary WordPress plugin – it can contain code that shapes what WordPress does  –  but it has a few advantages such as:

  • runs earlier in the WordPress loop
  • cannot be deactivated
  • applies to all sites in a multi-site WordPress install

Being ran earlier in the loop is important when you need to ensure your code runs before another plugin.

To create a “Must-Use” plugin you will need access to the files and folders on your server – this may be through your web host’s “cPanel” account or FTP.

  1. Browse to the wp-content directory
  2. Create a new directory called mu-plugins – so you have /wp-content/mu-plugins
  3. Open the mu-plugins directory
  4. Create a new text file and give it a name followed by .php – for example itsg_mu_plugin.php
  5. This leaves you with /wp-content/mu-plugins/itsg_mu_plugin.php
  6. Edit the file and add the following to the top of the file (you can change the details to suit)
  7. <?php
    Plugin Name: itsupportguides.com must-use plugins
    Description: code that always runs
    Version: 1.0.0
    Author: IT Support Guides
    Author URI: itsupportguides.com
  8. Save the changes – you now have a “Must Use” plugin!
  9. To use – add your custom functions below the */ line