Shopify Developer – Simple US Customs Duty Estimator App (Milestone Based)

Description: We're looking for a Full-Stack Shopify Developer to build a lightweight SaaS app for the Shopify App Store: a simple US customs duty estimator that shows an estimated import fee at checkout for US-bound orders. This is intentionally simple — no HS code lookups, no external tariff databases, no AI classification. Merchants set their own duty % and flat surcharge per product tag in a settings dashboard; the app multiplies that against the cart value at checkout and displays it as a clear line item. Flat subscription price to merchants: $7/month, unlimited use. Scope: Merchant dashboard (Shopify Polaris + React/Remix) — tag-to-rate mapping table Checkout calculation via Shopify Delivery Customization Functions + Checkout UI Extensions Shopify native billing integration (App Pricing / RecurringApplicationCharge), 14-day trial Built and tested first as a Custom App on a dev store, then submitted for public App Store review Requirements: Proven experience with Shopify GraphQL Admin API, Shopify Functions, Checkout Extensibility, App Bridge At least one/two app you've previously published live on the Shopify App Store (please link it) Node.js/Remix or Ruby on Rails, plus React Structure: Fixed-price, 3 milestones. Milestone 1 opens the contract at $80 USD; later milestones funded on delivery. To apply: Start your proposal with "Landed Cost Engine" to confirm you've read this fully. Include your live app links, your estimated timeline, and your total budget for Milestones 2–3. Estimated Budget Milestone Deliverable Typical range 1 Dashboard UI + architecture 2 Checkout calculation engine, working on dev store 3 Billing integration, testing, App Store submission Also remember won't be increasing the budget at the end of the contract so bid carefully fixed rate. If I need help during the project you must politely do so.