Shopify POS can't sell by weight. So like most market vendors, I ran two systems — Square for in-person, Shopify for everything else. Two catalogs, two logins, manual reconciliation every tax quarter. I built PopUp because I needed it. PopUp adds weight-based selling to Shopify POS. Mix weight and flat-price items in the same cart. On-device catalog, no Shopify inventory needed, works offline. Pause between seasons, no data lost.

• Sell by weight or by item — price calculates instantly at the point of sale
• Catalog stored on the device — opens instantly, no fetching data delays
• Simple catalog with no inventory required, works alongside Shopify
• Mix market items and existing store products in the same transaction
• Pause between seasons — your catalog data is waiting when you return