Backend & systems·API and interface design
you put one component in front of all the services to do auth, rate limiting and routing once instead of in each of them.
API gateway
A single entry point handling cross-cutting concerns — authentication, rate limiting, routing, request logging — for services behind it. It removes duplicated middleware and gives one place to enforce policy. It is also a shared choke point and a place for business logic to accumulate where nobody owns it.