Google's open-source remote procedure call framework, released in 2015, is gRPC.
The name originally referred to Google's next-generation RPC system, developed as an open-source successor to Stubby, the internal framework Google had used for communication among its enormous network of microservices. Google announced gRPC publicly in February 2015 and described it as a high-performance framework based on HTTP/2.
In gRPC, a client can call a procedure on a remote server almost as if it were a local function. Developers commonly define services and message types with Protocol Buffers, or protobuf, and tools then generate client and server code in multiple programming languages. HTTP/2 provides features such as multiplexed streams and efficient header compression.
A common mix-up is confusing gRPC with JSON-RPC or Apache Thrift. Those are also RPC technologies, but gRPC is Google's particular framework, strongly associated with protobuf and HTTP/2. The lowercase “g” is part of the official styling.