Plugin Development 101 – What Makes a Plugin?

In this first real part of the Plugin Development 101 tutorial series we look into what makes a plugin. How is a plugin different than any other .php file? How do you make WordPress recognize your code as a plugin?

A plugin in WordPress is really nothing more than a PHP file (or multiple PHP files) with a very specific piece of information included at the top of the file that has been placed in the wp-content/plugins/ folder.

There is no minimum or maximum for what a plugin can or must do. Plugins can be a single line of code, or 50,000 lines of code. Regardless of the size of a plugin, it is defined as a plugin in exactly the same way: by a piece of meta data placed in the main file.

At the top of every WordPress plugin is a comment block that contains information about the plugin:

• The name of the plugin
• A brief description of the plugin
• The URL of the plugin’s homepage
• The author of the plugin
• The author’s website
• The plugin version number

The meta data is always placed in a comment block, so like: