@MartinL I’ll also add that @JamilAhmed implemented a use case that sounds similar to yours (REST request in via MicroGateway and request handled in the backend by Cloud Stream apps) in this repo: GitHub - itsJamilAhmed/scs-credit-card-demo: A sample financial services use-case implementation of request-reply messaging using Spring Cloud Streams and Solace PubSub+ Binder
That might be of interest to check out 