01 What is gRPC

gRPC is a contract-first RPC framework from Google. You define messages and services in a .proto file, and gRPC handles serialization (Protocol Buffers) and transport (HTTP/2) for you. Both client and server agree on the contract before any code runs — no guessing at JSON shapes.

Key properties:

• Contract-first — .proto is the source of truth.
• Strongly typed — fields have explicit scalar or message types.
• HTTP/2 — multiplexed, binary, low-latency.
• Polyglot — the same .proto generates stubs for Go, Java, Python, Node, and more.

In this tier you stay in Node.js and skip code generation entirely: the @grpc/proto-loader package loads the .proto at runtime.

Set up the project

mkdir greeter && cd greeter
npm init -y
npm install @grpc/grpc-js @grpc/proto-loader

You'll work with three files: greeter.proto, server.js, and client.js (plus the shared load.js helper). Nothing else is needed.

Next: 02 Define the proto