Function Friday #0: functionality plugins vs. the functions file

Function Friday #0

This is the first post (T minus 1, really) in a series I’ll be doing every Friday in 2017. In each post I’ll share a neat code snippet for WordPress development, both ones I’ve been using for a while and ones I’ve just come across for the first time.

Before kicking it off, though, I wanted to do a little breakdown of where this code should actually go!

In a functionality plugin

If you’re adding functionality to a WordPress site that can work independently of the current theme, the best place for your code is a plugin. Putting it in a plugin means you (or someone else) can switch the theme without having the functionality disappear.

The minimum you’ll need to create a custom plugin is a single PHP file placed in the wp-content/plugins directory, with an opening PHP tag and the required header information within a comment at the top:

Plugin Name: Functionality Plugin for A. Client
Description: Custom functionality for A. Client's website.
Version: 1.0
Author: Linn Oyen Farley
Author URI:

All you really need is the plugin name, but you might as well help your client – or future you – remember what this plugin is for.

Name the plugin and the PHP file something unique, so it won’t conflict with existing plugins. If it’s for a client, I’ll include the client’s name in the plugin name (as above) and then repeat it for the file name, e.g. a-client-functionality.php.

Then below the comment, add your code. Zip up that PHP file (so you get something like, upload it via Plugins → Add New, and activate it. That’s it!

In a theme’s functions file

Some WordPress developers are super hardcore about keeping all custom functionality theme-independent, but I’m a bit more lax about it – if I’m adding custom functionality that ties into theme layout/design, I’ll put it in the theme’s functions.php file. You are welcome to be as hardcore or lax as you want, of course!

You probably already have a functions file going (because you’re properly enqueuing your stylesheets and scripts, right?). If you don’t, you’ll want to create a file named functions.php in the main theme folder and start it with an opening PHP tag:


I also usually include a comment at the top with a table of contents to keep it organized.

That’s it for this week! Suggestions for future posts and corrections to existing ones are always welcome.

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