Uni-Uni to Vigo/Sella Integration

I need Uni Uni’s shipping API wired seamlessly into both my Vigo and Sella Cloud environments. The goal is to have every new order that appears in either platform pushed automatically to Uni Uni for fulfillment, then returned with the carrier label and tracking number in real time.

Key workflow
• Orders leave Vigo/Sella Cloud the moment they are created and carry over all relevant fields (items, quantities, customer address, priority flag).
• Uni Uni responds with the shipment details, which must post straight back so warehouse staff see the label and tracking link instantly.
• A simple rule set drives the hand-off: high-priority orders move first; all others queue behind them. This priority field already exists in the database, so the logic can key off it.

I’ll provide API keys for all three systems plus endpoint documentation from Uni Uni. You handle the authentication handshake, build the event listener/webhook, code the priority-based routing, and test end-to-end so that I can drop a live order and watch it flow through without manual touches.

Deliverable
1. Clean, commented source (language is your choice) packaged for deployment on our AWS Lambda instance.
2. Postman collection or cURL scripts that demonstrate each call.
3. A brief setup/readme and a 15-minute hand-over call so my in-house dev can maintain it.

If you have completed similar shipping automations, show me a reference or quick demo link; it will speed up selection.