API Gatewayの概要

An API Gateway is the smart front door to your backend — essential once you split an app into many microservices.

With many microservices, each has its own address and auth, and a client may need several calls per task. That sprawl gets messy fast — and a gateway tames it.

An API Gateway is a single entry point for all client requests. Instead of calling services directly, clients hit the gateway, which routes each request.

A reverse proxy forwards at the network level; an API Gateway goes further — adding auth, rate limiting, and transformation at the application layer.

The big win: clients only need one URL. The gateway hides your messy internal service layout, making client code simpler and less error-prone.

A gateway centralizes security: authentication checks who you are, authorization checks what you can do, and rate limiting stops abuse — all in one place.

The gateway routes requests by rule (e.g. /users to the User Service) and load-balances across service instances so none gets overloaded.

Beyond routing, API Gateways often add monitoring, logging, caching, request/response transformation, and even protocol translation.

Without a gateway, a mobile app makes 3 calls to 3 services. With one, it makes a single call and the gateway aggregates the responses for it.

Which of the following are typical benefits or features provided by an API Gateway in a microservices architecture?

Recap: an API Gateway is the single entry point for microservices — simplifying clients, centralizing security, and routing with load balancing.