Essential Plugins for WordPress Theme Development

by Ryan Cowles May 1st, 2013 

Creating a WordPress theme is no simple task. But if you're like me, you'll find that it can be very rewarding and fun. In this article I am going to share some of the plugins that I use to make this process a little bit easier.



The Developer plugin is a great place to start. According to its description in the WordPress plugin repository, it "helps WordPress developers develop." And that is absolutely correct. It's main purpose is to help developers install several very helpful and important plugins. When you install and activate the plugin it prompts you to select which type of developer you are - Plugin, Theme, etc. From there, it will check to see which plugins you already have installed. It will then recommend which plugins you should install. With one click of the mouse, you can easily install and activate the recommended plugins.

Debug Bar


The Debug Bar is a great plugin within itself. It provides you with information about requests, memory usage, and more on the front end of your site. What makes it even more powerful is the fact that there are several other plugins that extend this functionality even further. For example, Debug Bar Extender can be installed to further the functionality of the Debug Bar. The plugin's page in the WordPress repository states that it, "is mainly aimed at developers who like to debug their code or want to measure runtimes to find glitches in their code. It also allows lookup of variables by adding simple code snippets in your source." It will let you check SQL queries, analyze caching, and a lot more.

Debug Bar Hook Log will add a new tab to the Debug Bar that displays all the hooks called during the current page request. You can even click on each hook to expand it and see which arguments were passed.

Debug Bar Console is pretty straightforward, but very powerful. It adds a convenient PHP/MySQL console to the Debug Bar. This lets you debug PHP and MySQL problems without requiring SSH access to the server.

Log Deprecated Notices

As the name implies, this plugin will log the usage of deprecated files, functions, and arguments. It also lets you know where they are being used and even provides an alternative method that you can use instead.

What The File


When you are developing a WordPress theme, it can be easy to "get lost" when working on multiple files. I know there have been times I'm updating one template file, and can't figure out why it isn't updating on the front end, only to find out that I was editing the wrong file. What The File is a very simple solution to this problem. It simple adds a new item to the toolbar that lets you see which template file is generating the current page. Problem solved.

Monster Widget


Monster Widget is a real time saver when you are developing a theme. It combines all of the core widgets and allows you to create multiple instances of each. Instead of having to manually create thirteen different widgets to test their appearance in your theme, you can just use Monster Widget and review them all.

Regenerate Thumbnails / AJAX Thumbnail Rebuild


These two plugins essentially do the same thing, and both have saved me from countless headaches. During the theme development process, I often find myself adding, editing, and removing various image sizes. WordPress doesn't have a default way to regenerate all the thumbnails, so if I have existing content, I need to resize the thumbnails to include my new image sizes. Both of these plugins allow you to do just that.

Note: Both of these plugins are great. I find myself using the AJAX Thumbnail Rebuild on larger installs, so it doesn't timeout the server.

Theme Check


The Theme Check plugin was developed to check your theme against the latest Theme Review Standards put forth by Even if you aren't planning on publicly releasing your theme, this plugin can be a huge help. It's very easy to use, and it will provide warnings and suggestions in a nice list.

Theme Test Drive / Development Theme


After you have developed and tested your theme, one of the last steps is putting it live on your production site. This can be scary. Either of these two plugins should help make the change a little less scary. They will both let you to take your theme for a test drive. It will allow administrators who are logged in to view the site with the new theme, while still serving the old theme to your regular site visitors. You can then poke around and make sure everything is working correctly.


Developing themes for WordPress is a passion of mine, but even I know that there can be frustrations throughout the process. Over the months and years, I have found that the above plugins have saved me from quite a few gray hairs - and I hope they help you as well. And if you have any plugins that you think should be added, I would love to hear about them!

Ryan Cowles

Ryan Cowles is a WordPress / Front End Developer living in Los Angeles, California. Along with a passion for building creative websites, he also enjoys photography, design, travel and the great outdoors. You can view his personal website by visiting To see what he has been up to lately, check out his blog at Metacom Creative.

Ryan S. Cowles

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3 Responses to “Essential Plugins for WordPress Theme Development”

  1. Hi Ryan,

    These are great plugins. I recently started learning more about creating WordPress custom themes. These would make the process difficult for me. Do you also use a dummy content generator plugin? What would you recommend?

    Thanks for sharing these!

  2. Abdus says:

    Thank you Ryan for sharing a nice collection of plugins. I personally like Debug Bar plugin

  3. […] Essential Plugins for WordPress Theme DevelopmentĀ – Creating a WordPress theme is no simple task. But if you're like me, you'll find that it can be very rewarding and fun. In this article I am going to share some of the plugins that I use to make this process a little bit easier. […]