gRPC, Explained

What gRPC actually is - a contract-first way for internal services to call each other fast - how the .proto file, code generation, and HTTP/2 streaming fit together, and the real trade-offs versus REST and GraphQL.

1. The Problem gRPC Solves Internal services that call each other thousands of times need both speed and a strict typed contract; gRPC answers with contract-first design (Protocol Buffers) and compact binary messages over HTTP/2.
2. How gRPC Works The .proto file defines services and messages; a code generator turns it into client and server stubs in many languages; messages travel as compact binary; and gRPC offers four call types - unary plus three streaming modes.
3. The Real Trade-offs gRPC's binary payloads aren't human-readable and need special tools to debug; browsers can't speak it directly without grpc-web and a proxy; the learning curve is real. It shines for internal microservice traffic and is a poor fit for public, browser-facing APIs - with a fair REST-vs-GraphQL-vs-gRPC table.