How to Create a WordPress Plugin (Beginner’s Guide)

Key Takeaways

• Developing a WordPress plugin allows for personalized features, better performance and improved compatibility with your website’s needs. 
• The process involves creating a PHP file, adding a header, writing custom code and testing the plugin within WordPress. 
• Submitting your plugin to the WordPress repository requires creating a readme file, following specific guidelines, and using SVN for updates. 
• Secure your plugin by sanitizing inputs, using nonces and validating outputs to protect against vulnerabilities. 
• Creating plugins builds web development skills and offers monetization opportunities through plugin sales or premium features.

Introduction

Whether you’re an aspiring developer or a website owner eager to expand your site’s capabilities, learning how to create WordPress plugin opens up a world of customization. Crafting a custom WordPress plugin allows you to tailor your website to precisely fit your needs, offering a level of flexibility that off-the-shelf plugins can’t always provide. By building a new plugin for the website, you’ll not only gain control over added functionality but also avoid unnecessary features that can bloat your site and slow down performance.

Creating a WordPress plugin might seem complex, but with the right guidance, it’s a manageable and rewarding process. In this beginner’s guide, we will walk you through the essential steps to build a functional new plugin, how to effectively integrate it into your site, and tips for tailoring it to meet your specific goals. Whether you’re looking to add a unique feature or simply learn the ropes of plugin functions and development, this guide has everything you need to get started and elevate your website’s capabilities. 

Why develop a WordPress plugin

Creating a WordPress plugin allows you to customize your website to meet your unique needs while also enhancing its functionality and adaptability. Take a look at these main justifications for why developing a unique WordPress plugin is good for you:  

Customization  

Using WordPress plugins, you may provide your website with special features and capabilities that aren’t available in pre-made themes or many WordPress plugins. This modification allows you to create a custom user experience for your visitors.  

Performance optimization  

You can minimize any damaging effects on the performance of your website by creating a custom plugin that is light and effective. It helps yield better user experiences and quicker loading times. As the users find it easy to access the website, the ROI increases gradually and puts your brand on the map.

Compatibility  

While developing plugins from scratch, you can make sure that your plugin is compatible with WordPress core updates, other plugins, and your website’s theme. By doing this, you can keep your website running smoothly and steer clear of any future problems. 

Security  

By having complete control over the code, you can put strong security measures in place. This lowers the possibility of vulnerabilities that might put your website’s security at risk and enable smooth operations for the owner as well as the users.

Monetization  

By putting your valuable existing plugins up for sale on different markets, you may be able to make some money from it. Offering premium features or support services can increase your revenue because it can appeal to a variety of users who require more advanced functionality or dedicated assistance. 

Additionally, if you update and refine the functions continuously based on feedback, your premium plugins will maintain their relevance and desirability in the marketplace. This can improve product quality while also fostering user trust and loyalty.

Development of skills  

Learning the ropes of creating a WordPress plugin allows you to gain knowledge about the WordPress platform and improve your web development skills. As you delve into plugin development, you’ll become proficient in PHP, JavaScript and possibly SQL. The custom function additions are essential for crafting an effective WordPress plugin. This experience also enhances your problem-solving abilities as you navigate through the plugin code challenges and integration issues. Over time, you can expand your skill set to include new themes and change WordPress functionality along with custom website solutions. This then broadens your expertise and makes you a more versatile developer in the tech community. 

How to create a WordPress plugin step-by-step guide 

Step 1: Create your first WordPress plugin

1. Begin by creating a new folder in your desktop or document directory and giving it a name like “plugin-tutorial” or “new-plugin.”  
2. Next, create a new file using your preferred text editor and save it within the plugin folder as “plugin-tutorial.php” or “new-plugin.php.” Ensure that the file has a .php extension, but the name itself can be anything you choose. 
3. Open a new PHP file with your text editor to begin editing.
4. First, add the plugin header to your file. This comment block informs WordPress of your plugin name, version, website, author name, and other relevant information.
5. After adding the header of WordPress plugin, you can start writing the custom code underneath it. 
6. In this example, we will create a simple plugin that appends a message at the end of each article, encouraging users to follow us on Twitter. 
7. Copy and paste the following code below your header block of the main plugin file, making sure to replace the Twitter and Facebook profile URLs with your own before saving the changes.

<?php 

function wpb_follow_us($content) {

// Only do this when a single post is displayed 

if ( is_single() ) {  

// Message you want to display after the post 

// Add URLs to your own Twitter and Facebook profiles 

$content .= '<p class="follow-us">If you liked this article, then please follow us on <a href="http://twitter.com/wpbeginner" title="WPBeginner on Twitter" target="_blank" rel="nofollow">Twitter</a> and <a href="https://www.facebook.com/wpbeginner" title="WPBeginner on Facebook" target="_blank" rel="nofollow">Facebook</a>.</p>'; 

} 

// Return the content 

return $content;
} 

// Hook our function to WordPress the_content filter 

add_filter('the_content', 'wpb_follow_us');

8. Now, navigate to your computer’s desktop and create a zip file containing the plugin’s folder. 

9. For Mac users, right-click on the folder and select “Compress plugin-tutorial.” Windows users can right-click on the folder and choose “Compress to zip file.” 

Step 2: Install and activate your first WordPress plugin

Now that the custom WordPress plugin has been created, it’s time to install and test it. For detailed instructions, refer to our guide below on installing a WordPress plugin. 

1. Navigate to your website’s WordPress admin area and go to Plugins > Add New. 
2. Click the Upload Plugin button at the top to reveal the plugin upload box. 
3. Select the Choose File button to pick the zip file you recently created. Then, click the Install Now button to upload and install the plugin. 
4. Once the installation is complete, activate the plugin.
5. Now, visit your website to see the plugin in action. 

All of your single posts now have a new paragraph at the end. 

Step 3: Submit your plugin to the WordPress.org plugin repository

To increase your plugin’s visibility and usage among WordPress users, you can submit it to the WordPress.org plugin repository. 

1. First, you’ll need to create a ‘Read Me’ file for your plugin. Open a blank text file and save it as readme.txt in your plugin folder. 
2. The readme.txt file should follow WordPress.org’s readme file syntax, as the information you include here will be displayed on your plugin’s page on WordPress.org. 

Readme file syntax

Let’s briefly discuss the WordPress plugin readme file syntax so you can customize even for a simple plugin. 

1. The first line of the readme file should be your plugin name, which will be displayed as the plugin’s title in the WordPress.org plugin directory. 
2. The next line is Contributors, which lists the user IDs responsible for managing your plugin on WordPress.org. If you don’t have an existing user account, you can create a free one to obtain your user ID. 
3. ‘Requires at least’ and ‘Tested up to’ indicate the WordPress versions your existing plugins are compatible with, while ‘Stable tag’ refers to your plugin’s version.
4. You can keep the ‘License’ fields as GPL and retain the same URL. 
5. Next, edit the Description section to explain your plugin’s functionality. 
6. After editing your plugin’s readme file, remember to save your changes. 
7. Your plugin is now ready for review by the WordPress.org plugins team. To submit your plugin, you’ll need a free WordPress.org account. 
8. Go to the Add Your Plugin page, and if you’re not logged in, click the please log in button. 
9. Once logged in, you can upload and submit your first plugin for review. 
10. Click the Select File button to choose your plugin’s zip file, then check all applicable boxes and click Upload. 

The WordPress.org plugin review team will examine your plugin code for common errors and security checks. After approval, you’ll receive an email with a link to your plugin’s Subversion (SVN) repository hosted on WordPress.org. 

Step 4: Using Subversion (SVN) to upload your plugin

Subversion is version control software that enables users to modify files and directories while maintaining a record of changes, managing different versions and facilitating collaboration. 

Installing an SVN client on your computer is necessary to upload your own plugins to WordPress.org. Windows users can use SilkSVN or TortoiseSVN (free), while Mac users can install SmartSVN or Versions App. 

We’ll demonstrate the process using the Versions App for Mac. However, the procedure is quite similar across all SVN apps with a GUI. 

Steps to upload the plugin

1. After installing the app, open Versions and check out a copy of the repository of your WordPress plugin by clicking the New Repository Bookmark button. 
2. In the popup, provide a name for this bookmark (preferably your plugin’s name) and add your WordPress plugin’s SVN repository URL. 
3. Click Create to connect to your repository. 
4. Versions will download a copy of your plugin’s repository to your computer. Right-click on your repository name in the browser view and select Checkout. 
5. Specify a folder name and location for storing the local copy of your WordPress plugin on your computer, then click Checkout. 
6. Versions will create a local copy of your plugin. Copy your plugin files and paste them inside the trunk folder of your local repository. 
7. You’ll see a question mark icon next to new files in Versions. Select the new files and click Add to include them in your local folder. 
8. Now, click on your local repository and hit Commit. 
9. In the resulting popup, you’ll see a list of changes and a box to add a commit message. Click Commit to proceed. 
10. Your SVN app will sync your changes and commit them to your plugin’s repository. 
11. After uploading your plugin files to the trunk, tag them with a version. 
12. In the local copy of your plugin, copy the files inside the trunk folder. Then, open the tags folder and create a new folder within it. Name it after the version number. Ensure that the version number matches the one in your plugin’s header. 
13. After adding the new folder in the /tags/ folder, you’ll see a question mark icon next to the folder name in the Versions app. Click Add to include the folder and its files in the repository, then click Commit to sync your changes. 

Pro tip

You can continue editing your separate files of plugin in the local copy and commit changes to sync with the WordPress.org repository. If you make significant changes to your plugin, create a new version by putting it in a new folder named after the version number. Make sure this version number matches the one in your plugin’s header. 

You can now preview your plugin in the WordPress.org plugins directory. 

Step 5: Add artwork to your plugin on WordPress.org

WordPress.org allows you to include artwork and screenshots with your simple WordPress plugin. These elements must adhere to standard naming conventions and be uploaded using Subversion. 

Plugin Header Banner 

This large image appears at the top of the plugin page and can be either 772 x 250 or 1544 x 500 pixels in JPEG or PNG file formats. It should always be named as follows:

• banner-772×250.jpg or banner-772×250.png  
• banner-1544×500.jpg or banner-1544×500.png  

Plugin Icon 

This smaller, square-shaped image file is displayed as a plugin icon in search results and plugin listings. It can be either 128 x 128 or 256 x 256 pixels in jpeg or png file formats. 

The icon file should be named as follows: 

• icon-128×128.jpg or icon-128×128.png
• icon-256×256.jpg or icon-256×256.png 

Screenshots 

Screenshot files should be named using the following format: 

• screenshot-1.png 
• screenshot-2.png 

Reminders: 

1. You can add as many as you like, and these screenshots should appear in the same order as the screenshot descriptions in your readme.txt file. 
2. Once you have prepared all the artwork, place it in the assets folder of your plugin’s local copy. 
3. Afterward, you will notice a question mark icon next to the assets folder. Click the Add button to include the new asset file in your repository. 
4. Lastly, click the Commit button to upload your files to the WordPress.org repository. After some time, the artwork will appear on your plugin page. 

Common plugin issues & quick fixes 

Creating your own WordPress plugin can come with challenges, especially for beginners. Here are some common issues you might encounter and quick solutions to get your plugin file running smoothly: 

Syntax errors 

A simple typo, like a missing semicolon or mismatched brackets, can lead to frustrating errors on the WordPress site. Using a code editor with syntax highlighting can help you spot these issues quickly. Make sure to review your code for common syntax mistakes and test frequently to catch errors early.

Compatibility issues 

When you create a WordPress plugin, it can sometimes clash with other plugins or themes. For instance, multiple files of plugins trying to alter the same part of the site can lead to unexpected behavior. Always test your plugin file in a staging environment first, enabling the WP_DEBUG mode in WordPress, which provides detailed error logs for troubleshooting. 

Plugin activation errors 

Sometimes, plugins for your WordPress website won’t activate due to missing files or incorrect file paths. WordPress is case-sensitive, so double-check that file names match exactly and that all necessary files are in place. If you encounter an activation error, review the file paths and naming conventions. This is an important step in WordPress development process.

Addressing these common issues early in plugin development can save you time and help ensure a smoother plugin launch. 

Best security practices

Ensuring the security of your own WordPress plugin is vital to protect both your users and their websites from potential vulnerabilities. By following these best practices, you can create a more secure plugin: 

Sanitize inputs 

To prevent security vulnerabilities like SQL injections and cross-site scripting (XSS) attacks, it’s crucial to sanitize any input from users. WordPress offers several sanitize_*() functions that make it easy to clean and validate input data, which helps protect your plugins folder against malicious input. 

Use nonces for verification 

When your plugin code performs actions on behalf of the user, such as submitting a form, using WordPress nonces (numbers used once) adds a layer of protection against Cross-Site Request Forgery (CSRF) attacks. Use functions like wp_create_nonce() and check_admin_referer() to verify requests and ensure they’re coming from an authorized source. 

Validate output 

Just as you sanitize inputs, it’s important to validate output. Use WordPress functions like esc_html() or esc_url() to escape data output, especially if it’s dynamic or user generated. This step helps prevent unintended scripts from running on your site and keeps your WordPress site plugin secure. 

By incorporating these security measures, you can make your plugin more robust and trustworthy, giving users greater confidence in its safety. 

Advanced customization options 

For developers looking to enhance their plugins with advanced functionality, the WordPress website provides several tools for customization. Here are some options to add more versatility to your WordPress plugin development: 

Creating plugin settings 

Offering settings for your new plugin development allows users to customize their experience and adjust features to suit their needs. Use add_options_page() to create a settings page in the WordPress admin panel, and register_setting() to save the settings data securely. 

User roles and permissions 

To control access to specific plugin features, you can assign custom user roles and permissions. For example, you might create a “Plugin Manager” role that grants access to certain administrative functions. WordPress’s add_role() and add_cap() functions make it easy to manage roles and capabilities, helping you create a tailored experience for different users. 

Adding hooks and filters 

Make your plugin more flexible by utilizing a suitable WordPress function like hook and filter. These allow other developers to modify and extend your plugin without altering its core code. Adding WordPress hooks and filters not only improves compatibility but also enhances the plugin’s modularity, making it easier to update and maintain over time. 

These advanced options can turn a basic plugin into a powerful, user-friendly tool that meets various needs and adapts to different site requirements. 

Create your own plugin today!

Learning how to create a WordPress plugin is a fantastic skill that boosts your website’s functionality and helps you kickstart a career in web development. This beginner’s guide has walked you through the essential steps to develop, test and submit your plugin to the WordPress.org repository. 

By sticking to the outlined best practices, you’ll make sure your WordPress site plugin is safe, efficient and works well with different WordPress themes and plugins. Plus, creating custom plugins can open up new opportunities for making money and growing professionally in the field of web development. As you continue to develop your skills and take on more complex projects, you’ll find yourself able to create unique, customized solutions for your core WordPress system.

Create a WordPress plugin FAQs