For building the seller authentication flow, integrators can create a seller logged-in UI, where the seller can initiate the auth flow <Follow the Link> or merchants can log in to Seller Central and authorize the integrator’s app. <Follow the Link>.
a. To test the auth flow, developers need to identify a test seller account to authorize and produce the auth code.
b. Using the auth code and client/app credentials, the integrator’s app will be able to extract and refresh the token by calling <OAuth> endpoint.
c. Now using client/app credentials and the refresh token, the app can extract the access token from SP-API <OAuth> endpoint.
d. This access token can be used to call <Production> and <Sandbox> endpoints.
Note: Only outbound interface sandbox responds with dynamic responses and others like Listings, inbound and inventory interfaces respond with static responses as per their swagger models.
e. Upon completion, the app will be able to fulfill MCF orders for merchants by connecting to Production endpoints. Note: Seller listings and inbounded inventory are required for order previews and order fulfillment.