Amazon SP-API OMS Integration

I need our in-house Order Management System to talk seamlessly with Amazon through the new SP-API. All Seller Central credentials still have to be generated, so your first task will be to walk me through that process and make sure OAuth, refresh tokens, and roles are configured correctly.

Once the keys are active, I want real-time order synchronisation, inventory synchronisation, and product listing pushed and pulled automatically. The solution must work across multiple Amazon marketplaces from the same code-base; I should be able to add an additional region later without rewriting anything.

Please bring proven experience with Amazon SP-API (or its predecessor MWS), solid understanding of OAuth 2.0, and prior work integrating e-commerce/OMS platforms. Bonus points if you have already connected to platforms like Flipkart, Meesho, or Shopify, but the Amazon piece is the priority and it is time-sensitive.

Deliverables
1. Live SP-API connection with authentication flow fully operational
2. Endpoints/functions for order, inventory, and product data mapped to our OMS tables
3. Error handling and logging so issues are easy to trace
4. Final hand-off with concise technical documentation and a short knowledge-transfer call

The timeline is tight, so only respond if you can start immediately and hit the ground running.