grpc

name	grpc
description	Build high-performance gRPC services with Protocol Buffers — service definitions, unary and streaming RPCs, interceptors, error handling, and Node.js/Go implementations
layer	domain
category	backend
triggers	["grpc","protobuf","protocol buffers","proto file","gRPC streaming","gRPC service","rpc call","grpc-web","tonic grpc","connect-rpc"]
inputs	["Service interface and method definitions","Language/runtime (Node.js, Go, Rust, Python)","Communication pattern (unary, server-streaming, client-streaming, bidirectional)","Authentication and authorization requirements","Deployment target (Kubernetes, Cloud Run, bare metal)"]
outputs	["Proto file definitions with message and service schemas","Server implementation with interceptors","Client stubs with retry and deadline configuration","Streaming handler implementations","Error handling with gRPC status codes","Build configuration for proto compilation"]
linksTo	["api-designer","microservices","authentication","monitoring"]
linkedFrom	["microservices","api-designer"]
preferredNextSkills	["monitoring","testing-patterns"]
fallbackSkills	["api-designer"]
riskLevel	low
memoryReadPolicy	selective
memoryWritePolicy	none
sideEffects	[]

gRPC Skill

Purpose

gRPC is a high-performance RPC framework using Protocol Buffers for serialization and HTTP/2 for transport. It provides strongly-typed service contracts, automatic code generation, bidirectional streaming, and efficient binary serialization — making it the standard for service-to-service communication in microservice architectures. This skill covers proto file design, server/client implementation in Node.js and Go, streaming patterns, and production hardening.

Key Concepts

gRPC vs. REST

Aspect	gRPC	REST (JSON)
Serialization	Protobuf (binary, ~10x smaller)	JSON (text)
Transport	HTTP/2 (multiplexed)	HTTP/1.1 or HTTP/2
Contract	.proto file (strict)	OpenAPI/informal
Streaming	Native (4 patterns)	Workarounds (SSE, WebSocket)
Code generation	Built-in for 11+ languages	Optional (openapi-generator)
Browser support	Via grpc-web or Connect	Native
Debugging	Needs tooling (grpcurl, Evans)	curl, browser

Four Communication Patterns

1. UNARY (request-response):
   Client ──request──→ Server
   Client ←──response── Server

2. SERVER STREAMING:
   Client ──request──→ Server
   Client ←──stream──── Server (multiple responses)

3. CLIENT STREAMING:
   Client ──stream──→ Server (multiple requests)
   Client ←──response── Server

4. BIDIRECTIONAL STREAMING:
   Client ←──stream──→ Server (both directions)

gRPC Status Codes

Code	Name	When to Use
0	OK	Success
1	CANCELLED	Client cancelled the request
2	UNKNOWN	Server threw an unexpected exception
3	INVALID_ARGUMENT	Client sent bad input (400 equivalent)
5	NOT_FOUND	Resource does not exist (404 equivalent)
6	ALREADY_EXISTS	Conflict on create (409 equivalent)