What is WordPress Core? WordPress Core Explained

The term “WordPress core” encompasses all the foundational files that a WordPress website requires to work. In this article, we’re going to take a look in detail at the core of WordPress. By the end, you’ll know exactly what WordPress core means, what it does, how you can contribute to WordPress, and a lot more.

Now, let’s dive in.

As you’re probably already aware, WordPress as a content management system is pretty easy to use on the surface. Almost anyone with a basic understanding of websites can design and run a successful WordPress site. What makes WordPress so popular is that you can do this without needing to know what’s going on behind the scenes.

At some point, however, you’ll probably want to have a better understanding about the core files that run your website.

Knowing what’s going on under the hood of your WordPress website can help you do things like troubleshoot errors and issues beyond what you can do in the WordPress admin dashboard.

Once you’re more familiar with WordPress core files, where you can find them, and what they each do, you’ll open a new world of development opportunities for your site. You will also learn how to quickly troubleshoot your own site issues, and eventually be able to install a few custom features just like a pro.

Key Points

• ‘WordPress core’ refers to the essential files required for a WordPress site to function, including the wp-config.php and functions.php files.
• Understanding WordPress core enables users to troubleshoot issues and customize their sites beyond the admin dashboard.
• Core files are separate from themes and plugins, which are necessary for building a visible website.
• Why core modifications should be made in theme-specific functions.php files.
• How regular updates of WordPress core benefit site security.

The Four Core Parts of a WordPress Website

Before we jump in, let’s cover some basics. Every website that runs on WordPress consists of four distinct parts.

If you want to successfully work with WordPress, it’s important to understand the four basic components of all WordPress websites:

1. WordPress core files
2. The WordPress database
3. WordPress theme files
4. WordPress plugin files

What is WordPress Core? 

WordPress core is a way of referring to all the “foundational” files that are required for WordPress to work. WordPress core is what you download from WordPress.org in the form of a zip file.

Core WordPress files allow you to do things like:

• Access the WordPress admin dashboard
• Add and edit posts and pages
• Manage users
• Upload media files
• Delete content
• Add tags and categories
• Embed videos
• Allow users to reply and comment
• … and a lot more

If you want to see exactly what the core of WordPress is, all you need to do is remove all themes and plugins from your WordPress dashboard. You now have only the core.

When you strip your website back to only the core of WordPress, the first thing you’ll notice is that you can’t build or view your website with only the core files installed. You need a WordPress theme activated in order to start creating a site for public consumption.

That’s why when you first install WordPress, you’ll notice that it automatically includes a few generic themes that you can start working with to make your site visible. But the standard themes included in a WordPress install aren’t technically a part of its core.

Without the help from a theme or plugin, the core of WordPress carries out all of these functions on its own. However, it doesn’t do everything you need it to do to build your website. Beyond WordPress core, you’ll need themes and plugins to create your website.

WordPress Core Files

Two of the most important core WordPress files include:

• wp-config.php – This file controls all the basic settings of your WordPress website, including your database connection information.
• functions.php – This file is one of the most important operating files of WordPress. Important note: Your theme also has a  functions.php file, and that’s the file you need to edit, not the core file contained in the base directory of your website.

The top-level core WordPress folder has a lot of other files that are very important to the way your site works. For the purposes of practicality, most of your troubleshooting time (if any) will be spent in the .htaccess and wp-config.php files.

There are also two important folders in WordPress core:

• wp-content – This folder contains your plugins, themes and media uploads.
• wp-admin – This folder contains all the files that power the WordPress admin dashboard.

Don’t worry if these names sound like Greek to you right now. We’ll discuss each one in more detail in a bit.

If you do proceed to edit core files in WordPress, always avoid changing any of the code unless you have a thorough understanding of exactly what you’re doing. Be sure to make a backup of your website with a WordPress backup solution like Solid Backups — NextGen before making any changes to WordPress core files.

A Look Inside the WordPress Core Zip File

To get a look inside the WordPress core file, you simply need to expand the zip file on your computer. When you expand the WordPress zip file you downloaded earlier from WordPress.org, you’ll see this file listing:

These important WordPress core files are included with every installation of WordPress and are found in the main (top) directory once they are installed on your server.

How to Access the WordPress Core Files of Your Website

To access the backend core WordPress files of your website, you’ll need to download and install an sFTP client such as FileZilla (completely free and works perfectly on all operating systems). This will allow you to directly access the WordPress files.

You’ll then need to connect to your website’s server via the SFTP client with the credentials you were given by your website host. If you aren’t familiar with what your credentials are, talk to your hosting provider.

You can also use the File Manager provided by your WordPress host. The most common file manager platform is cPanel.

The wp-config.php File

The wp-config.php file provides the base configuration details for your WordPress website.

The wp-config.php file contains necessary information to make your WordPress website operate, including MySQL database connection settings, WordPress salts & keys, WordPress database table prefix, WordPress language and ABSPATH (the absolute path to the WordPress directory).

The functions.php File

WordPress includes two distinct files named functions.php, and understanding the difference between them is key to avoiding mistakes:

• Core functions.php: Located in the wp-includes directory, this file is part of the WordPress core. It powers fundamental operations across the platform and should never be edited. Modifying this file can break your site and will be overwritten during WordPress updates.
• Theme-specific functions.php: Each theme in WordPress can have its own functions.php file found in the theme’s folder (e.g., /wp-content/themes/your-theme/functions.php). This file is safe to edit and is used to add or customize functionality specific to your website’s theme.

Here’s an example directory tree to help you visualize the hierarchy of both files:

WordPress Installation ??? wp-admin/ ??? wp-content/ ?   ??? themes/ ?   ?   ??? your-theme/ ?   ?   ?   ??? functions.php (Theme-specific file for customizations) ??? wp-includes/ ?   ??? functions.php (Core WordPress file; do not edit)

With the functions.php file you can add customized functions (makes sense, right?) to your website by developing your own. Of course, you’ll have to understand PHP first. You can also use this file to call on predefined functions that you want to apply to your site.

Pro tip: To ensure your changes are safe and update-proof, use a child theme and edit its functions.php file for customizations instead of editing the file of the parent theme. Alternatively, consider creating a custom plugin to add functionality that isn’t tied to a specific theme.

WordPress wp-admin Folder

The majority of files that power the WordPress dashboard live within the wp-admin folder. A glance through the files inside the wp-admin folder will reveal a different file for nearly all core WordPress features.

admin.php

What we’re interested in right now is the file called admin.php. This is the file at the very root of your /wp-admin folder. It works to enable a large number of your website’s most crucial features, including:

• Loading the WordPress dashboard
• Connection to your database

In addition, the admin.php file checks user credentials and applies their permissions accordingly.

Some other noteworthy core files within the directory include:

• users.php (controls user administration panels)
• update.php (explains itself)
• network.php (oversees multisite functionalities)

WordPress wp-content Folder

The wp-content folder, for the most part, houses the plugin and theme files related to your site. It doesn’t house anything that’s tied directly to the core of WordPress. Because of this, we’re going to focus on the wp-includes folder in this article.

WordPress wp-includes Folder

Think of your wp-includes folder as the one that’s storing all of “the rest” of the files that power your WordPress site. In other words, as wp-admin is working to govern your administration tools, the wp-includes folder is the one making everything possible.

When you open the wp-includes directory, you’ll immediately notice how large it is. In fact, there are well over 100 individual files in the folder’s top level. Obviously, we can’t cover every one of these here.

Once you’re more familiar with WordPress core files, where you can find them, and what they each do, you’ll open a new world of development opportunities for your site. You will also learn how to quickly troubleshoot your own site issues, and eventually be able to install a few custom features just like a pro.

Note: After seeing how many files support your WordPress installation, no doubt you see many areas that could be potential security risks. To protect your site at all times, a WordPress security plugin like Solid Security Pro is an absolute must-have.

Components of a WordPress Website Not Included in WordPress Core

Now that we’ve covered WordPress core files, let’s go over what isn’t included in the WordPress core files.

• The WordPress database – The WordPress database stores most of the content of your WordPress site.
• The .htaccess file – This file is usually hidden, so you need to enable the Show Hidden File option to access it. Just note that some hosts no longer support this file.
• WordPress theme files – Your WordPress theme files are separate from WordPress core.
• WordPress plugin files – WordPress plugin files also are separate from core.

What’s interesting about plugins is that once in a while, a plugin gains a huge amount of popularity and millions of installs from WordPress developers. When this happens, there’s often a push to have that plugin added as part of a standard WordPress install.

What this actually means is that the plugin will become part of the core of WordPress. And that’s exactly how the core evolves.

WordPress Core Updates: How to Update WordPress Core

WordPress often sends out updates to its core to deal with new security threats and issues with functionality. WordPress core updates often include exciting feature additions and enhancements, too.

So when it comes to your website, it’s important to know how to update WordPress.

We strongly recommend updating to the latest version of WordPress as soon as possible as a WordPress security best practice. Why? Running outdated versions of WordPress core, plugins and themes is the #1 reasons WordPress sites get hacked.

You can update WordPress and its core files using a one-click update option within your WordPress dashboard. When there’s a new version of WordPress available, you’ll typically see a “new version” banner link at the top of your admin area.

Just click on the Update Now button and run the update of WordPress.

If you don’t see a banner, navigate in your dashboard to the Updates menu. When you find the Update WordPress page, click Update Now and the process will start running.

Once the process finishes, your site will be running the new core WordPress version.

Note: To save time running WordPress core updates, a tool like Solid Security Pro can help. The platform’s Version Management Feature simplifies the management of updates for WordPress core, themes, and plugins. It allows users to set custom update rules, including the ability to automatically update to new versions of WordPress and manage plugin/theme updates with more flexibility than the default WordPress options. For those managing multiple sites, combining Solid Security Pro with our centralized management dashboard Solid Central allows you to manage updates for up to 50 sites with ease.

How Do I Restore a Core WordPress File?

The quickest, smartest and easiest way to restore core files is by using a software solution  such as Solid Backups — NextGen. When you use a cloud-based platform like this, core WordPress files can be restored from backup versions saved prior to when the file was corrupted. 

If you’d rather restore files manually, you’ll still need to make sure you’ve saved a backup version of your site before beginning.

To upload and restore core files, you can use SFTP or your File Manager. Locate the files you’d like to restore from within the directory of your backup version.

If you’re using SFTP, you’ll be able to upload your chosen files without needing to zip them. We discussed how to transfer files via SFTP earlier in the article.

If you’re using File Manager, the files you upload will need to be the .zip version.

Follow these steps if you’re using the File Manager:

1. Upload your backup files to the proper directory in the core of WordPress.

2. After the upload is done, go to that folder and select Reload.

3. Select the .zip file and click Extract.

4. Refresh to see your files.

5. Select all and move them to public_html (the site’s root).

Finally, remove the index.html file by either deleting it or changing its extension to a name that web browsers won’t render.

Head to your site URL and refresh it. If you restored the files properly, your site will be back up and running.

How Do I Contribute To WordPress Core?

If you’re a developer, you may be interested in contributing to WordPress. By doing so, you’d be one of the individuals who built the platform that every WordPress user installs on their sites and servers.

The WordPress platform consists of a wide array of developers that use various tools to improve the way the platform operates. Some of the tools these developers use include:

• Javascript
• PHP
• MySQL
• And more

But improving code isn’t the only improvement that these developers make. They also improve WordPress core by releasing updates, fixing bugs, testing new patches, reporting vulnerabilities in security and a ton more.

If you’re interested in getting involved as a developer in contributing to core development, check out the Make WordPress Core page and get started. If you end up stuck on a project, you can use the WordPress handbook (located on the same page) for quick reference.

You will want to follow current core development updates on the WordPress developer page. Developers who want to stay in the loop of what is going on within the core of WordPress will find a lot of key information there.

If you’re interested in becoming a beta tester for WordPress core, download and install the WordPress Beta Tester plugin.

WordPress Beta Tester

This plugin gives you a simple way to become part of the WordPress beta testing community. Once you’ve installed the plugin, you’ll be able to upgrade your site to the latest WordPress beta release and start providing feedback to the community.

What is WordPress Core? Now You Know

Understanding the WordPress core is essential for anyone looking to effectively manage their website. The core comprises the foundational files that enable WordPress to function, including critical components like the wp-config.php and functions.php files. Familiarity with these elements not only aids in troubleshooting but also opens up opportunities for customization and development. 
To enhance your WordPress experience, consider utilizing Solid Security Pro’s automated update features, alongside Solid Backups — NextGen, to ensure your core files are backed up and easily restored if needed. If you’re managing multiple sites, check out what Solid Central can add to the party, and remember that all three solutions are available within our fabulous Solid Suite!