API Gateway
In plain terms
A single front door that routes and manages requests to backend services.
Going deeper
An API gateway sits between clients and microservices, handling routing, authentication, rate limiting, and aggregation in one place. It simplifies clients and centralizes cross-cutting concerns.
Under the hood
Centralizes auth, rate limiting, routing, and request aggregation but can become a bottleneck or single point of failure if not made highly available.
Examples
AWS API Gateway, Kong, NGINX, Azure API Management, Apigee.
Think of it like...
Like a hotel front desk: guests make every request there, and the desk routes it to housekeeping, the kitchen, or maintenance behind the scenes.