[robertlagrant]

Go and Dart are probably the languages most likely to work well with gRPC, given their provenance.

[throwaway127482]

Google has massive amounts of code written in Java so one would think the Java tooling would be excellent as well.

[9rx]

Doesn't Google mostly use Stubby internally, only bridging it with gRPC for certain public-facing services?

[p_l]

Google also uses a completely different protocol stack to actually send Stubby/Protobuf/gRPC around, including protocols on the wire and bypassing the kernel (according to open access papers about PonyExpress etc)