Amazon Seller Central API Integration

I need an engineer who already knows the Amazon Selling Partner API inside-out to wire it into our current web-based application. My team has built the front end and core business logic; what we’re missing are the secure, well-structured endpoints that let us talk to Seller Central in real time.

Here’s what the integration must cover:
• Inventory management – pull catalog details, update quantity and pricing, sync FBA / FBM stock levels.
• Order processing – fetch new orders as they arrive, push acknowledgements, handle shipping confirmations and tracking uploads.
• Data reporting – schedule and retrieve financial, performance and returns reports, then pipe the data into our existing dashboards.

For authentication we expect you to set up the SP-API LWA and Role-based IAM flow, handle token refresh, and keep throttling under control. Code needs to drop cleanly into our web stack (Node.js + PostgreSQL), but I’m open to another language if you provide rock-solid wrappers and clear documentation.

Deliverables:
1. Documented REST layer (or SDK wrapper) that exposes the three functional areas above.
2. Deployment scripts and env-variable template for staging and production.
3. A brief hand-off session walking my devs through usage, rate limits, and error handling.

I consider the job done when our staging server can:
• List active SKUs and show stock parity with Seller Central.
• Receive a new order notification within the API’s expected window and push a fulfilment update that appears in the Seller Central portal.
• Download a settlement report on demand and parse it into our existing tables with no data loss.

If you have prior SP-API projects, please mention them and note which parts you handled end-to-end.