Stickmarks review for Checkout Upsell — Addonn

Jan. 21, 2026

Addonn is exactly what i was looking for, Best and one of a kind app i found so far for upselling add-ons at checkout on Shopify app store. Customer support is very responsive and helped me set up the app correctly on my store, I wanted little custom functionality and it got delivered in just couple days. The best part is that it works without adding any additional codes to the theme. I highly recommend it!