How to Set Up a Klaviyo Back‑in‑Stock Flow for Shopify Stores

Klaviyo now lets Shopify merchants automate restock alerts by linking a “Notify me” form to a back‑in‑stock flow that triggers when inventory returns. The flow starts when a shopper signs up for a restock alert, generating a Subscribed to Back in Stock event on their Klaviyo profile, which then queues the customer until the product is restocked [2].

The platform offers two ways to capture the alert request. Merchants can use Klaviyo’s built‑in form builder—available for Shopify and BigCommerce—or embed a code snippet directly into their theme files, which automatically displays a “notify me when available” button on out‑of‑stock pages [2]. Once the form is live, the flow can be created from Klaviyo’s library: navigate to the Flows tab, select “Create flow,” and filter by the “Remind people to purchase” goal or search “back in stock” to pull a pre‑built template [2]. After importing the template, brands should customize the email copy to match their voice and keep the sequence short, typically one to three messages, to avoid overwhelming subscribers [2].

Why the setup matters is clear: Shopify stores lose sales when items run out, with a 2024 AlixPartners study showing 66 % of shoppers turn to competitors in that scenario [1]. Back‑in‑stock emails achieve open rates above 50 %—roughly double typical automated campaigns—and can recover a sizable portion of those missed purchases [1]. By integrating the alert form with Klaviyo’s flow, merchants also consolidate subscriber data, enabling follow‑up campaigns such as welcome series, product recommendations, or cross‑sell offers without juggling separate apps [1].

Klaviyo’s flow also respects inventory across channels; if a retailer uses Shopify POS alongside its online store, the flow counts stock in both the physical outlet and the warehouse, ensuring alerts fire only when the item truly becomes available [2]. Best‑practice tips include enabling Smart Sending for non‑essential messages and timing emails so customers have enough time to act [2].

The real test for merchants will be whether the added automation translates into measurable recovery of lost sales and higher customer loyalty, especially as they balance notification frequency against the risk of email fatigue.