Restockly: Back in Stock adds a signup widget to your sold-out product pages. When a product runs out of stock, customers can enter their email to join a waitlist for that specific product or variant. When you restock the item in Shopify, the app sends an automatic email notification to everyone on that waitlist.You can view all active waitlists, subscriber counts, and sent notifications from the app dashboard. The email template is customizable so it matches your store's branding.