Theme customization VS Plugin development

Maximizing WordPress: Diving Into Theme Customization vs. Plugin Development

August 04, 2020Posted By: Cristopher Parmar
Plugin DevelopmentTheme CustomizationWordPress


A few years ago, WordPress’ popularity was limited to the blogger community. Later, as developers became interested in the power of content management systems (CMS), WordPress became the go-to space for complex website creation and WordPress development. This evolution brought about a greater emphasis on customizing WordPress themes and developing plugins to extend functionality, offering users endless possibilities for tailoring their websites to suit specific needs and preferences.

When to Use Theme Customization vs. Plugin Development In WordPress

Nowadays, we can develop any kind of website using WordPress. In fact, through continuous evaluation, WordPress has developed advanced plugin customization and themes to curate indispensable websites.

Today, over 30% of websites are powered by WordPress due to its flexible and simple features. The unparalleled level of customization that WordPress provides helps a lot of developers by making their lives simple and easy.

Deciding Between Theme Customization And Plugin Development For Functionality

In a developer’s journey, there are multiple junctures where they might have to choose one of the many options laid out in front of them. In one such case, a developer ponders the choice between plugin development and theme customization. Both of these choices are equally important and beneficial, but sometimes, a developer might have to choose just one.

Let’s take an example: You want to add a custom price to the checkout page based on some product quantity using dynamic calculation using the Woo-commerce plugin. However, no plugin is available that can fit your requirements. There are often two ways to achieve this functionality. You can either add the code to the activated theme or develop a new WordPress plugin that will have all the functions that you need.

Some WordPress developers think that adding the code to functions.php is easy and the right way to go. However, this is not true; depending on your needs, you can develop a WordPress plugin. In this article, we will discuss the pros and cons of plugin development vs. the functions.php file and find which method is better.

Write Custom Code In functions.php File

Writing code in the theme’s functions.php file is always simple and easier than developing your plugin. Some developers often use custom code in themes.

While this File can work as your plugin, the bottom line remains that it is not a plugin.

We know that themes are mainly used for design, fonts, and layout. However, we can also use themes for some basic customization.

Let’s now discuss the advantages and disadvantages of adding code to functions.php file.

Benefits Of Adding Code To functions.php Or In Theme

  • It uses code to make theme-related changes, like featured image function, excerpt length, widgetized areas, etc.
  • Admin functions.php can easily change the files in WordPress. You cannot change this in the plugin because once you update it, it’ll overwrite the changes, and you’ll have to start from scratch.
  • You can add, change, and delete any of the snippets in the file.
  • You can easily check the code and understand it properly.
  • Sometimes, snippets are hard to find in the plugin, whereas they are easy to find in the theme.
  • It will save developers a lot of time.
  • You can include multiple files for different theme functionalities.
  • It is easy to work on CSS if your functions are in the themes.

Challenges Of Adding Code To functions.php Or In Theme

  • The functionality is limited to the theme you are working on. So, the code will not work for other themes once you switch them.
  • Once you update the theme, all changes will overwrite it unless you have a child theme.
  • It is hard to understand the code because you have created a lot of functionality using the theme.
  • It is difficult to disable/enable the functionality from the admin. Whereas the plugin allows that with ease.
  • Themes are a framework, and as you add more plugins, they become more functional. So, it is better to use plugins.

There are many ways you can customize the code on your site. However, it will never replace the WordPress plugin. A plugin and adding code snippets to your functions.php file will have the same effect on performance.

Plugin Development

There are many plugins available in WordPress that can make a developer’s life easier. However, it is not possible to get plugins for some complex functionality. In such a case, we can develop our plugins.

Let’s take the above pricing customization example. For these kinds of requirements, you may write code in functions.php. However, if the functionality is complex, I would recommend developing your plugin.

Plugins can be used on any website, whereas theme customization will work for the particular theme. The main benefit of developing the plugin is that you can always use the hooks to extend functionality to the plugins.

Benefits Of Developing Plugins

  • A WordPress plugin does not depend on the theme. We can install plugins on any WordPress site.
  • Plugins will not have any performance issues if they are the same code as the functions.php file.
  • Plugins are always easy to disable, update, or reinstall as needed.
  • You can easily identify the plugin’s functionality from the plugin’s description.
  • You can add your custom style and scripts to the plugin. Which will not be included when the plugin is deactivated.
  • You can use the plugin’s shortcode for the functionality of the pages or posts.
  • Plugins allow us to customize the WordPress admin & dashboard. You can always disable it.
  • If the plugin is updated or changed, it might not affect your site unless there is an error.
  • If you have some customized code for the theme using plugins, it will work the same.
  • As I said above, you can always deactivate the plugin if it stops working or you have any issues.
  • You can develop the plugin using OOPS concepts, which will make the plugin more secure.
  • Hooks are always better for extending functionality via theme files.
  • To track/debug the issue, simply deactivate the plugin
  • You can enable/disable features if you suspect there is a conflict.
  • Once you create a complex plugin, you can upload it to the WordPress plugin repository and sell it to customers who need it.

Challenges Of Developing Plugins

  • It will take more time and effort to develop the plugin for small functionality.
  • It may conflict with other plugins with the same name, functions, or methods.
  • It may not be compatible with all the themes.


So, as we discuss some of the advantages and disadvantages above, we can get an idea of both features. If there are theme-related changes, like an excerpt length change, an image size change, etc., you can add the code to the functions.php file. However, for complex functionalities, directly editing the theme files is not recommended. It can make theme updates difficult and lead to maintenance issues down the road.

A better approach for complex website customizations is to develop a separate WordPress plugin. This keeps your theme clean and easier to manage and simplifies future updates. WordPress plugin development is a core skill for many web developers, and there are plenty of resources available to help you get started.

If plugin development feels outside your comfort zone, outsourcing your WordPress development needs can be a smart option. Companies like ZealousWeb can create a custom plugin that meets your specific requirements and integrates seamlessly with your WordPress website.


What Is Theme Customization?

What Is Plugin Development?

Can I Achieve Complex Functionalities With Theme Customization Alone?

How Do Theme Customization And Plugin Development Affect Website Performance?

Can I Use A Combination Of Theme Customization And Plugin Development?

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