# grpc [gRPC](http://www.grpc.io/) is an excellent, modern IDL and transport for microservices. If you're starting a greenfield project, go-kit strongly recommends gRPC as your default transport. One important note is that while gRPC supports streaming requests and replies, go-kit does not. You can still use streams in your service, but their implementation will not be able to take advantage of many go-kit features like middleware. Using gRPC and go-kit together is very simple. First, define your service using protobuf3. This is explained [in gRPC documentation](http://www.grpc.io/docs/#defining-a-service). See [add.proto](https://github.com/go-kit/kit/blob/ec8b02591ee873433565a1ae9d317353412d1d27/examples/addsvc/pb/add.proto) for an example. Make sure the proto definition matches your service's go-kit (interface) definition. Next, get the protoc compiler. You can download pre-compiled binaries from the [protobuf release page](https://github.com/google/protobuf/releases). You will unzip a folder called `protoc3` with a subdirectory `bin` containing an executable. Move that executable somewhere in your `$PATH` and you're good to go! It can also be built from source. ```sh brew install autoconf automake libtool git clone https://github.com/google/protobuf cd protobuf ./autogen.sh ; ./configure ; make ; make install ``` Then, compile your service definition, from .proto to .go. ```sh protoc add.proto --go_out=plugins=grpc:. ``` Finally, write a tiny binding from your service definition to the gRPC definition. It's a simple conversion from one domain to another. See [grpc_binding.go](https://github.com/go-kit/kit/blob/ec8b02591ee873433565a1ae9d317353412d1d27/examples/addsvc/grpc_binding.go) for an example. That's it! The gRPC binding can be bound to a listener and serve normal gRPC requests. And within your service, you can use standard go-kit components and idioms. See [addsvc](https://github.com/go-kit/kit/tree/master/examples/addsvc) for a complete working example with gRPC support. And remember: go-kit services can support multiple transports simultaneously.