How to Create a Back in Stock Function with Klaviyo on Shopify

When customers see an “Out of Stock” message, it can mean a lost sale. But with Klaviyo’s Back in Stock feature, you can turn that moment into an opportunity—letting shoppers subscribe for notifications and automatically emailing them once the product is restocked. Here’s a step-by-step guide to setting it up in Shopify.

Why Use Back in Stock Alerts?

• Recover sales – Customers who sign up are already interested.
• Improve customer experience – Shoppers don’t need to constantly check back.
• Collect intent data – Each signup shows demand for specific products.
• Guide inventory decisions – Identify your most requested items.

- Step 1: Install Klaviyo on Your Shopify Store

1. In Shopify admin, go to Apps > Shopify App Store.
2. Search for Klaviyo: Email Marketing & SMS and install it.
3. Connect your Shopify store to your Klaviyo account

Once connected, Shopify will sync your product catalog and customer data with Klaviyo.

- Step 2: Enable Back in Stock in Klaviyo

1. Log into Klaviyo Dashboard.
2. Navigate to Signup Forms > Back in Stock (create a new form for the first using)
3. Choose Enable Back in Stock and link it to your Shopify store.
4. Klaviyo will automatically generate a Back in Stock signup form that attaches to out-of-stock product pages.

- Step 3: Customize the Signup Form

• Button text – e.g., “Notify Me When Available” instead of “Out of Stock.”
• Fields – usually just email, but you can add SMS if you want text alerts.
• Styling – match your theme’s fonts, colors, and button styles.

In Shopify, preview the product page and ensure the “Notify Me” button appears when inventory is 0.

- Step 4: Create a Back in Stock Flow

This is the automation that emails customers when the product is replenished.

1. In Klaviyo, go to Flows > Create Flow.
2. Select Back in Stock Flow (Klaviyo provides a pre-built template).
3. Customize:
   • Email Subject – “Good news, [Product Name] is back in stock!”
   • Timing – Send immediately or add a short delay.
   • Design – Add product images, description, price, and a direct Shop Now button.

Make sure to test the flow by restocking a test product.

- Step 5: Test the Full Experience

1. Set a product’s inventory to 0 in Shopify.
2. Visit the product page and subscribe to “Back in Stock.”
3. Restock the product in Shopify.
4. Check if the Klaviyo flow sends the notification email.

- Step 6: Optimize and Analyze

• Add SMS – Offer text alerts for faster conversions.
• Limit stock alerts – If you restock only a few units, consider setting a cap (so hundreds of people don’t get disappointed).
• Track performance – In Klaviyo reports, review open rates, click-throughs, and conversions.

Final Thoughts

Klaviyo’s Back in Stock function is one of the simplest yet most effective ways to recover lost sales and keep customers engaged. Once set up, it runs automatically, saving you time while boosting revenue.

If you want to go further, you can:

• A/B test subject lines for higher open rates.
• Segment customers who signed up for Back in Stock into retargeting ads.
• Combine with SMS for instant alerts.