Shopify App Developer Needed - Complete & Launch Production-Ready Shopify App

QR Centraal is a SaaS platform that enables businesses to generate smart QR codes, create mobile landing pages, manage digital menus, run campaigns, and track analytics - all in one place. We now want to extend our ecosystem by launching a public Shopify app that integrates seamlessly with our platform. What We’ve Built So Far - Basic Shopify app scaffold (details shared after NDA) - Partially completed OAuth and authentication flow - Early-stage UI integration with QR Centraal APIs Scope of Work You will: - Review current code and architecture - Complete unfinished features and refine existing functionality - Improve integration with QR Centraal REST APIs (and Webhooks if needed) - Implement Shopify Billing API (subscription model) - Ensure app passes Shopify App Store approval requirements - Build production-grade error handling, security hardening & performance improvements - Set up automated deployment flow and best practices - Assist with final testing, bug fixing, and documentation Ideal Skills & Experience You should have: - Proven experience building and launching public Shopify apps - Strong knowledge of Shopify ecosystem: OAuth, Admin API, Storefront API, Webhooks, Billing - Experience with React, Node.js/NestJS - Experience integrating third-party SaaS via secure API flows - Strong understanding of performance, security, and scalable architecture - Familiarity with App extensions, UI components (Polaris), and theme app extensions is a plus - Bonus: Experience with analytics tracking (PostHog, Segment, etc.) Deliverables - Fully functional Shopify app ready for App Store publishing - Technical documentation for future maintenance - Deployment scripts & CI/CD setup - Passing QA checklist + Shopify approval Apply tot his job Apply To this Job