Canteen lets Shopify merchants automate mandatory deposit and fee rules, including bottle, can, keg, core, and container deposits (Pfand, CRV, Statiegeld, Consigne, Pant), refundable deposits, environmental and recycling fees, core charges, service, handling, convenience, and processing fees, surcharges, adult-signature fees, and security deposits. Build flexible rule sets with tax controls, custom thumbnails, detailed options, and Shopify POS support.