Smart Order & Inventory API

I’m building a central API that receives every new order from my Wix storefront, checks real-time stock across three nearby locations, compares both availability and price, then decides which store should fulfill the sale. Once the choice is made, the same service must decrement inventory at that location and raise an instant alert whenever stock dips below a threshold or sales spike unusually.

Because I have no existing back-end, the whole pipeline—orders, inventory, pricing, and alerts—needs to be created from the ground up. Orders integration is my top priority, so the initial milestone should prove that an order placed on Wix can travel through the API, retrieve inventory data, and respond with a recommended store.

I’m open to your suggested stack: Node.js with PostgreSQL, Firebase functions, Supabase, or any modern alternative. What matters is a clean, well-documented REST or GraphQL interface that I can later expose to an external dashboard. Please outline:

• architecture choice and why it suits a Wix front end
• how you’ll manage auth, rate limits, and webhooks
• endpoints required for orders, inventory, pricing, and alerts
• automatic inventory syncing logic across the three stores
• alert mechanisms you’ll use (email, SMS, push, etc.)

Acceptable deliverable: a working repository with environment setup notes, Postman or Swagger collection, and a brief deployment guide so I can run it on my preferred cloud host.

If you can demonstrate a quick proof-of-concept order flow, you’ll have a strong edge.

The stores are Walmart, Bjs, wegmans, stop and shop, sams club, Costco, shop rite. I would like shopping carts can be fullfilled where items are available, i can manually pay. Please no generic answers