We Built a Shopify App. Here’s What Broke.

2026-03-03

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"Even if it ends up being something that ends the universe, it at least will have been a fun ride. So let's do it." That's what Karl Meisterheim said when Kurt pitched him on building a Shopify app. Over a year later, Promo Party Pro is live, and the journey from "this should be easy" to "why is the cart API doing that" was anything but smooth. Kurt, Paul Reda, and Karl sit down to talk through the whole thing: why free gift with purchase is Kurt's favorite promo, the edge cases that nearly broke them, the popup cooldown debate that consumed days, and what it...

"Even if it ends up being something that ends the universe, it at least will have been a fun ride. So let's do it."

That's what Karl Meisterheim said when Kurt pitched him on building a Shopify app. Over a year later, Promo Party Pro is live, and the journey from "this should be easy" to "why is the cart API doing that" was anything but smooth. Kurt, Paul Reda, and Karl sit down to talk through the whole thing: why free gift with purchase is Kurt's favorite promo, the edge cases that nearly broke them, the popup cooldown debate that consumed days, and what it actually takes to ship a polished app on Shopify in 2025.