Yes, it should be safe to expose gRPC C# as a public endpoint, but it obviously depends on you use case and the level of security/stability you are looking for. The key pieces of gRPC C# (the serving logic, authentication, encryption) is based on gRPC C core, which is intended to be safe to use as a public endpoint. On the other hand, we haven't really done any extensive testing with gRPC C# to be sure it is absolutely bulletproof. I think one could pull off a DoS attact against a gRPC C# server (but DoS is hard to prevent without a more sophisticated serving infrastructure anyway), but your data should be safe.