License your WordPress plugins with domain-mode

// In your plugin's main file, validate on admin_init
add_action('admin_init', function () {
    $response = wp_remote_post('https://api.licensr.app/v1/license/validate', [
        'headers' => [
            'Content-Type'  => 'application/json',
            'Authorization' => 'Bearer ' . YOUR_PLUGIN_API_KEY,
        ],
        'body' => wp_json_encode([
            'license_key' => get_option('my_plugin_license_key'),
            'plugin_slug' => 'my-plugin',
        ]),
    ]);

    // First run: call /v1/license/activate once with the site's domain (see the guide)
    $body = json_decode(wp_remote_retrieve_body($response), true);
    if (isset($body['valid']) && $body['valid'] === false) {
        // Disable premium features
    }
    // No answer (network error, 429, 5xx): keep the previous state
});