gRPC communicates via HTTP/2, implemented by a Netty server on the Content Server and Workflow Server. See Spring gRPC Server / Security / Netty for information on the configuration procedure for TLS or mTLS security. Mind that clients need to enable a corresponding configuration as well by referencing an SSL bundle via the client channel properties spring.grpc.client.channel.cap.ssl.bundle and spring.grpc.client.channel.wf.ssl.bundle (plaintext is used by default).