Automatic vs Manual
By default, back-in-stock emails are sent automatically when a product is restocked. You can switch to manual mode under WooCommerce → Settings → Waitlist → Notifications.
Customizing the Email
The notification email can be customized under WooCommerce → Settings → Emails → Back in Stock Notification. You can edit:
- Subject line
- Email heading
- Additional content
Batch Sending
When a product has many subscribers, emails are sent in batches to avoid overwhelming your mail server. The default batch size is 50 emails per minute.