The work starts in a Postman sandbox environment that the marketplace provides. Your first task is to spin up that sandbox, wire it to a fresh Shopify store, and confirm that authentication, product import, order creation, and fulfilment webhooks are all firing as expected. Once the sandbox is live, load a short catalogue of physical products—just enough to complete the test scenarios. I have all marketplace documentation and credentials ready to go; you bring the API expertise and clear communication so we can wrap this up quickly.