API gateways are software components that act as an entry point for client requests to access APIs. They provide a single, unified interface for clients to interact with multiple backend APIs, services, or Microservices. API gateways can be implemented using various technologies such as reverse proxies, load balancers, or application delivery controllers (ADCs).

API gateways handle request routing, security, traffic, versioning, governance, among other functions to ensure the reliability and appropriate usage of the APIs.