Chapter 1. An Introduction to Plugins


  • Understanding a plugin

  • Using available WordPress APIs

  • Loading order of plugins

  • Finding examples of popular plugins

  • Determining the separation of plugin and theme functionality

  • Managing and installing plugins

  • Understanding types of WordPress plugins

WordPress is one of the most popular open source content management systems available today. One of the primary reasons WordPress is so popular is the ease with which you can customize WordPress through plugins. WordPress has an amazing framework in place giving plugin developers the tools needed to extend WordPress in any way imaginable.

Understanding how plugins work, and the tools available in WordPress, is critical knowledge when developing professional WordPress plugins.


A plugin in WordPress is a PHP script that extends or alters the core functionality of WordPress. Quite simply plugins are files installed in WordPress to add a feature, or set of features, to WordPress. Plugins can range in complexity from a simple social networking plugin to an extremely elaborate e-commerce package. There is no limit to what a plugin can do in WordPress; because of this there is no shortage of plugins available for download.

How Plugins Interact with WordPress

WordPress features many different APIs for use in your plugin. Each API, or application programming interface, helps interact with WordPress in a different way. Following is a list of the main available APIs in WordPress ...

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