Kelso: Back in Stock Alerts

Out of stock does not have to mean out of luck. Kelso adds a Notify me when available button to your product pages, then sends back in stock alerts to every waiting customer the moment you restock. Built for reliability: two detection paths, an inventory webhook plus a reconciliation poll, because Shopify does not guarantee webhook delivery. Every send is logged from queued to delivered. Unlimited subscribers and variant level matching on every plan, including free.