Single entry point for all clients — centralises auth, rate limiting, routing, SSL, and observability.
# Popular gateways
# Kong -- open source, plugin ecosystem
# AWS API GW -- managed, Lambda integration
# Nginx -- lightweight, configurable
# Traefik -- Docker/K8s native
# Nginx routing example
location /api/users {
proxy_pass http://user-service:3001;
proxy_set_header X-Real-IP $remote_addr;
limit_req zone=api burst=20;
}
location /api/products {
proxy_pass http://product-service:3002;
}