Gateway

A network component that acts as an entry point or intermediary between different networks or services. Like a toll booth on a highway, gateways control and manage traffic flow. In cloud computing, common gateway types include API Gateway (manages API traffic), NAT Gateway (enables outbound internet access for private resources), VPN Gateway (connects on-premises networks), and Internet Gateway (connects VPCs to the internet). AWS, Azure, GCP, and OCI all offer managed gateway services.

An API Gateway sits in front of microservices, handling authentication, rate limiting, and request routing. Users call one gateway endpoint, which routes requests to the appropriate backend service.