Project Overview We sell personalized closing/promotional gifts to real estate agents. We're building a Shopify platform where agents prepay for a quantity of gifts at a volume rate, then redeem them one at a time over time — personalizing and shipping each gift as their clients close on homes. We have a detailed build spec ready to share; this post is to get scoped quotes for the full build. How it works An agent buys a quantity package of a product (e.g. 5 / 10 / 20 / 30 / 50 / 100 units). The more they buy, the lower the per-unit price. The prepaid units sit in their account as a balance with an expiration window (e.g. 18 months). Agents can hold balances across multiple product lines and buy more anytime. We hold blank inventory; nothing is personalized at purchase. When an agent has a closing, they log in, pick a product they have units for, personalize it (their client's family name prominently, plus the agent's own logo + signature in a discreet spot), and choose to ship to the client or to themselves. Each redemption decrements the unit balance and generates a print-ready production file for our warehouse. Core scope Prepaid unit/quantity balance system with per-product-line tracking and balance expiry (note: native Shopify store credit is dollar-based, so this likely needs a custom app or metafield-based ledger — your recommendation welcome) Quantity packages with descending per-unit pricing Agent account dashboard: units remaining per product, expiry dates, order history, reorder "Brand on file" — each agent's logo, signature, and default message stored once and auto-applied to every order Product personalizer with live preview (no manual proof step); outputs print-ready files Redemption checkout that draws from the unit balance ($0 out-of-pocket at redemption) Per-order ship-to choice (ship to client with address entry + validation, or ship to agent) Production output: clean, templated spec sheet per order for our fulfillment team A separate, simpler bulk-buy flow for branded giveaway items shipped to the agent Built to scale to thousands of agent accounts The key challenge (please address in your proposal) The hard part isn't the storefront — it's the prepaid unit balance with expiry (tracked per product line), plus per-redemption personalization, plus drop-shipping each order to a different recipient. Tell us how you'd architect the unit-balance ledger and how you'd handle the personalizer-to-production file flow. What we'll provide A detailed written build spec covering data model, redemption flow, phased delivery, and recommended app stack. Serious applicants get it to quote against. To apply, please include Links to past Shopify work, especially custom apps, customer portals, or product personalization Your read on the unit-ledger architecture question above A rough approach to phasing and a ballpark range Whether you'd build custom or lean on existing apps, and which Skills: Shopify custom app development, Liquid/theme app extensions, Shopify APIs & metafields, customer accounts/portals, product personalization apps (Easify/Zepto/Customily or similar). Engagement: Seeking quotes for a full build, open to milestone/phased delivery. Please propose a structure.