In Eclipse Vert.x version 4.3.0 to 4.5.9, the gRPC server does not limit the maximum length of message payload (Maven GAV: io.vertx:vertx-grpc-server and io.vertx:vertx-grpc-client).
This is fixed in the 4.5.10 version.
Note this does not affect the Vert.x gRPC server based grpc-java and Netty libraries (Maven GAV: io.vertx:vertx-grpc)