The grpc Gateway in Go worked quite well for us. I have not tried the native Envoy decoding functionality, yet. Also you should look at Google Artman on github

The grpc Gateway in Go worked quite well for us. I have not tried the native Envoy decoding functionality, yet. Also you should look at Google Artman on github/googleapis as sometimes it felt that defining the REST mappings in Protobuf were lacking some features. Using google artman you kind of mix/match Protobuf with yaml definitions of your service. We never had to use it, though. It just depends on where you want to put your authentication information. As of today I would probably change my mind and make it explicitly in payload, I.e. Protobuf message and not fiddle with headers any more.