My goal is to try to put both to work as part of the incremental migration from a REST API to gRPC. We are going to start using gRPC as the way of communication between our services in our microservice architecture.

The problem is that whenever I put the gRPC service in my middleware and/or I try to force http2 protocol for the gRPC to work my REST API stops to work. Even though my Swagger documentation stops to work with both implementations the endpoints via POSTMAN are still reachable when I add the middleware, but not when I add the http2 protocol. For reference we are already using .NET Core 3.

So my question is, is it possible to have both REST and gRPC working at the same time on the same application? If so, how?