Google had open sourced gRPC a Binary Remote Procedure Call Framework in 2015 and recently there was a 1.0 release of the new RPC framework which uses latest HTTP/2 and also uses Protocol Buffers v3.0 which is the latest release of Binary Serialization Protocol.
In the FAQs on grpc.io there is a mention that we still cant use it in browsers
But it is being currently used in mobile clients to communicate efficiently with servers/cloud servers.
Further Reading:
{apilevel.com} 