Custom Inventory, Sales, and Operations Management System with QuickBooks Online Integration

Custom Inventory Management System — Multi-Channel Distribution Business What we're building: We're looking for an experienced developer or small team to build a custom inventory management system to replace our current setup. The system needs to handle ~400 active SKUs across multiple sales channels (wholesale, Amazon, DTC e-commerce) and support warehouse operations end-to-end. Core deliverables -Multi-location inventory tracking with real-time stock levels -Lot/batch tracking with expiration date management and FEFO (first-expired, first-out) pick logic -Barcode scanning for receiving, picking, and cycle counts (web + mobile-friendly) -QuickBooks Online two-way sync (items, sales orders, invoices, bills, inventory adjustments) -Amazon SP-API integration (orders, inventory sync, FBA reconciliation) -Sales order and purchase order management -User roles and permissions (warehouse staff, sales, admin) -Reporting dashboard: stock on hand, aging inventory, expiring lots, reorder alerts, sales velocity by SKU Nice-to-haves (scope to discuss) -Shopify integration for DTC orders -Demand forecasting / reorder point automation -Kits and bundles handling -EDI-readiness for future wholesale customer requirements Skills we're looking for -Proven track record building inventory or ERP systems (please share examples) -Strong backend (Python/Django, Node.js, or similar) and modern frontend (React/Vue) -QuickBooks Online API experience (required, not optional) -Amazon SP-API experience (required, not optional) -Database design for transactional inventory systems -WMS workflow knowledge — FEFO, lot tracking, multi-location transfers -Clean documentation and code handoff practices How we like to work -Weekly check-ins (video calls) with clear written agendas and action items -Shared project board (Trello, ClickUp, or your preferred tool) with visible progress -Milestone-based delivery, not lump-sum — we want to see working pieces along the way -Direct, honest communication. If something is going to slip or a scope item is harder than expected, tell us early. We respond fast and don't disappear on you. -We'll provide detailed feedback and respect your time — no scope creep without a conversation -Final deliverable includes documentation, source code, and a knowledge transfer session To apply Please include: -2–3 examples of inventory or ERP systems you've built (live links or screenshots ideal) -Your proposed tech stack and a brief reasoning for why -A rough phased timeline and milestone breakdown -Your hourly rate or fixed-price estimate for an MVP scope -Answer this in your first line so we know you read the post: What's the trickiest part of building reliable lot/expiration tracking?