.NET gRPC

gRPC is a contract-first RPC system: you declare services and messages in a .proto, code is generated from it on both ends, and calls travel as Protobuf over HTTP/2. Reach for it when the producer and consumer are both yours and you want a typed contract, low overhead, and streaming - internal service-to-service traffic above all. Stay on REST when the surface is a public or browser-facing API where ubiquity and human-readable bodies matter more; those endpoints are dotnet-minimal-api. This skill covers gRPC and nothing else. Baseline is .NET 8 / C# 12.

The .proto is the single source of truth

The contract lives in the .proto, not in C#. Define every service and message there and let codegen produce the C# types; treat the generated *.cs as build output you never open or edit.

• Generate with Grpc.Tools (a build-time, dev-only package). Reference each proto in the csproj and pick the side that project needs:

  <ItemGroup>
    <Protobuf Include="Protos\orders.proto" GrpcServices="Server" />
  </ItemGroup>
  

  Use GrpcServices="Client" in a consumer, "Both" only when a project is both. The server generates an abstract base to override; the client generates a strongly typed stub.
• Share the contract by sharing the .proto, not the compiled assembly: keep protos in one folder (or a dedicated contracts project / package) that both sides reference, so server and client always regenerate from the same file.