The problem

When a product sells out, most Shopify stores just show "Sold Out" and the visitor leaves. That's a lost sale with no way to bring them back, and no record that they even wanted the item.

Why it matters

Back-in-stock emails aren't like regular marketing emails. The person already chose a specific product, they're not being sold to, they're waiting. That's why Omnisend's 2025 email data shows back-in-stock automations convert at 6.46%, the highest of any automated email type they track, well above standard promotional emails.

What we built

Custom code on the sold-out product page that lets customers enter their email to get notified. When the item restocks, that email is automatically pushed into Klaviyo, where it triggers a back-in-stock flow, no manual list exports, no app subscription fee.

The outcome

• Captures demand that would otherwise walk away

• Turns "sold out" into a lead-generation moment instead of a dead end

• Fully synced with Klaviyo for automated, trackable follow-up

• No third-party app cost, built directly into the theme