Shopify-Shopee Multi-Channel Sync

Built a serverless synchronization system for Inlinex that bridges their Shopify store with Shopee Singapore marketplace. The system runs on GitHub Actions with scheduled workflows: product sync pushes new and updated products from Shopify to Shopee with multi-image uploads, variant/size creation, and automatic category mapping. Inventory sync runs every 15 minutes to keep stock levels consistent across both channels, preventing overselling. Order sync pulls new Shopee orders into Shopify as draft orders and pushes fulfillment tracking back to Shopee. A separate Railway-hosted Express dashboard provides manual sync triggers and status monitoring. The system uses Shopee Open Platform API v2 with HMAC-SHA256 authentication and handles token refresh automatically via scheduled workflows.