Hello @rhino.lu,

Great question!

You can certainly add additional information as part of the back in stock API to be recorded and passed to Klaviyo. You can customize the back in stock API to pass your desired data without any issues so long as it is coded and executed accordingly. I would suggest working with a developer or finding a Klaviyo partner to further help you customize your back in stock API. I would also recommend taking a look at the following Help Center articles to learn more about how Klaviyo’s native back in stock API functions as well as how to leverage Klaviyo’s API:

• How to Install Back in Stock for Shopify
• How to Install Back In Stock for BigCommerce
• Shopify Back in Stock for Developers
• BigCommerce Back in Stock for Developers
• How Back in Stock Flows Work
• Getting Started with Klaviyo APIs
• Track and Identify API Reference
• Klaviyo's API Documentation

I hope this helps!

David