If you’re developing advanced plugins for WordPress, supporting multisite networks is a powerful way to extend your plugin’s usability across large installations. However, multi-site compatibility isn’t just about activating a plugin network-wide — it involves handling multiple databases, sites, and user contexts gracefully.

This guide walks you through how to create multi-site compatible plugins that are scalable, safe, and performant.

What is WordPress Multisite?

WordPress Multisite allows you to run multiple websites (called “sites” or “blogs”) from a single WordPress installation. Each site shares the same codebase but has:

• Its own set of posts, pages, options, and users.
• A shared wp_users table but different wp_{blog_id}_posts, wp_{blog_id}_options, etc.

Plugin Activation Options

When installing a plugin in Multisite, you can:

• Network Activate: Enabled on all sites.
• Site Activate: Enabled on selected sites only.

In your plugin, you must handle both scenarios correctly.

1. Register Network-Wide Hooks

register_activation_hook(__FILE__, 'myplugin_activate');

function myplugin_activate($network_wide) {
  if (is_multisite() && $network_wide) {
    // Loop through all sites
    $sites = get_sites();
    foreach ($sites as $site) {
      switch_to_blog($site->blog_id);
      myplugin_install();
      restore_current_blog();
    }
  } else {
    myplugin_install();
  }
}

function myplugin_install() {
  // Create custom tables, options, etc.
  add_option('myplugin_version', '1.0.0');
}

Use switch_to_blog() and restore_current_blog() for safe context switching between sites.

2. Use Site-Specific Data Functions

Avoid using get_option() for network-wide settings. Instead:

• Use get_site_option() and update_site_option() for network-wide settings.
• Use get_option() and update_option() for site-specific settings.

// For network-level settings
$setting = get_site_option('myplugin_network_option');

// For single-site settings
$setting = get_option('myplugin_site_option');

3. Manage Network vs Site Admin Screens

Differentiate admin menus depending on context:

if (is_multisite() && is_network_admin()) {
  add_menu_page('Plugin Network Settings', 'Plugin Network', 'manage_network_options', 'plugin-network', 'render_network_settings');
} else {
  add_menu_page('Plugin Settings', 'Plugin', 'manage_options', 'plugin', 'render_site_settings');
}

4. Use uninstall.php Carefully

If you’re cleaning up data, remember:

if (!defined('WP_UNINSTALL_PLUGIN')) {
  exit;
}

if (is_multisite()) {
  $sites = get_sites();
  foreach ($sites as $site) {
    switch_to_blog($site->blog_id);
    delete_option('myplugin_site_option');
    restore_current_blog();
  }
} else {
  delete_option('myplugin_site_option');
}

Avoid deleting shared user data or files unless absolutely necessary.

5. Handle Custom Tables Per Site

If your plugin creates custom database tables:

global $wpdb;
$table_name = $wpdb->prefix . 'myplugin_table';

$charset_collate = $wpdb->get_charset_collate();
$sql = "CREATE TABLE $table_name (
    id mediumint(9) NOT NULL AUTO_INCREMENT,
    value text NOT NULL,
    PRIMARY KEY  (id)
) $charset_collate;";

require_once(ABSPATH . 'wp-admin/includes/upgrade.php');
dbDelta($sql);

Ensure the prefix is site-specific (wp_2_, wp_3_, etc.).

Security Considerations

• Always check user capabilities with is_super_admin() for network-wide actions.
• Avoid assuming blog_id = 1 is the main site — always use get_main_site_id().

Bonus: WP-CLI Support for Multisite

Support automation with WP-CLI:

wp site list --field=blog_id | xargs -n1 -I % wp --url=% myplugin sync-data

In your plugin:

if (defined('WP_CLI') && WP_CLI) {
  WP_CLI::add_command('myplugin', 'MyPlugin_CLI');
}

Final Thoughts

Creating a multi-site compatible plugin involves more than toggling a checkbox. It requires:

• Smart use of switch_to_blog()
• Separation of site-wide vs network-wide settings
• Clean activation/deactivation routines
• Context-aware admin interfaces

Done right, your plugin can scale across dozens or hundreds of sites — powering SaaS platforms, school networks, enterprise CMS systems, and more.