You operate a single APIM API that must route traffic to one of two regional backends based on the X-Region request header (values: eu or us). The backends are preconfigured in APIM with backend-ids orders-eu and orders-us. You must keep a single API surface and route dynamically per request. What should you do?

The choose policy with set-backend-service is the correct approach because it allows dynamic routing to different pre-configured backends within a single API surface based on request headers. The choose policy evaluates conditions (like the X-Region header) and applies policies conditionally. set-backend-service then directs the request to the specified backend. rewrite-uri modifies the path of the request, not the backend host itself, so it cannot switch between different backend services. Creating two separate APIs would violate the requirement of maintaining a single API surface. A 302 redirect would force the client to make a new request directly to the backend, bypassing APIM for the second call, which is not the desired behavior for dynamic routing within APIM.