Creating a Plugin Licensing System for WordPress

Posted on 16th June 2023

Introduction

If you’re a WordPress developer, chances are you’ve thought about how to create a licensing system for your plugins. A licensing system can be a great way to generate revenue from your plugins, and it can also help you control who has access to your plugins and how they’re used. In this article, we’ll discuss how to create a licensing system for WordPress plugins.

Creating a License Key

The first step in creating a licensing system for your WordPress plugins is to create a license key. A license key is a unique code that is used to unlock a plugin. It is typically a alphanumeric string that is generated by a licensing system. When a user purchases a plugin, they are given a license key that they can use to unlock the plugin. License keys can be generated manually or automatically. If you’re selling your plugins on a marketplace such as CodeCanyon, your license keys will be generated automatically. If you’re selling your plugins directly, you’ll need to generate your license keys manually.

Adding a License Key Field to Your Plugin

Once you have your license keys, you’ll need to add a license key field to your plugin. This can be done by adding the following code to your plugin:

// Add a license key field to the plugin settings
add_settings_field(
    'license_key',
    'License Key',
    'license_key_callback',
    'my-plugin',
    'general'
);

function license_key_callback() {
    $value = get_option( 'license_key' );
    echo '';
}

This code will add a license key field to the general settings page of your plugin. The license key field will be populated with the license key that is saved in the database. If no license key is saved, the field will be empty.

Validating the License Key

Once you have a license key field in your plugin, you’ll need to validate the license key. This can be done by adding the following code to your plugin:

// Validate the license key
add_action( 'admin_init', 'validate_license_key' );

function validate_license_key() {
    $license_key = get_option( 'license_key' );

    // Your code here
}

This code will validate the license key when the plugin is activated. You’ll need to add your own code to this function to validate the license key. A license key can be validated by checking it against a database of valid license keys. If the license key is valid, the plugin can be activated. If the license key is invalid, the plugin can be deactivated.

Saving the License Key

Once you have a license key field in your plugin and you’ve validated the license key, you’ll need to save the license key. This can be done by adding the following code to your plugin:

// Save the license key
add_action( 'admin_init', 'save_license_key' );

function save_license_key() {
    if ( isset( $_POST['license_key'] ) ) {
        update_option( 'license_key', $_POST['license_key'] );
    }
}

This code will save the license key when the plugin is activated. The license key will be saved in the database and will be populated in the license key field when the plugin is deactivated.

Deactivating the Plugin

If the license key is invalid, you’ll need to deactivate the plugin. This can be done by adding the following code to your plugin:

// Deactivate the plugin
add_action( 'admin_init', 'deactivate_plugin' );

function deactivate_plugin() {
    // Your code here
}

This code will deactivate the plugin when the license key is invalid. You’ll need to add your own code to this function to deactivate the plugin.

Conclusion

In this article, we’ve discussed how to create a licensing system for WordPress plugins. We’ve covered how to create a license key, how to add a license key field to your plugin, how to validate the license key, and how to deactivate the plugin if the license key is invalid. Creating a licensing system for your WordPress plugins can be a great way to generate revenue and control who has access to your plugins.

In order to create a plugin licensing system for WordPress, you will need to first create a custom database table to store your license keys. You can do this by running the following SQL query:

CREATE TABLE `wp_licenses` (
`license_id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`license_key` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL,
`license_email` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL,
`license_name` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL,
`license_product_id` bigint(20) unsigned NOT NULL,
`license_expiry_date` date NOT NULL,
`license_status` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT ‘active’,
PRIMARY KEY (`license_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

Next, you will need to create a custom WordPress plugin to handle the license key checking. You can do this by creating a new PHP file and adding the following code:

sanitize_text_field( $license_key[‘license_key’] ),
‘license_email’ => sanitize_email( $license_key[‘license_email’] ),
‘license_name’ => sanitize_text_field( $license_key[‘license_name’] ),
‘license_product_id’ => absint( $license_key[‘license_product_id’] ),
‘license_expiry_date’ => $this->sanitize_license_expiry_date( $license_key[‘license_expiry_date’] ),
);

$sanitized_license_keys[] = $sanitized_license_key;
}

return $sanitized_license_keys;
}

public function sanitize_license_expiry_date( $date_string ) {
$date = date_create_from_format( ‘Y-m-d’, $date_string );

if ( false === $date ) {
return ”;
}

return $date_string;
}

public function render_page() {
?>