An API Gateway is a server-side architectural component in a software system that acts as an intermediary between clients (such as web browsers, mobile apps, or other services) and backend services, microservices, or APIs.

Its main purpose is to provide a single entry point for external consumers to access the services and functionalities of the backend system. It receives client requests, forwards them to the appropriate microservice, and then returns the server’s response to the client.

The API gateway is responsible for tasks such as routing, authentication, and rate limiting. This enables microservices to focus on their individual tasks and improves the overall performance and scalability of the system.

Difference between an API gateway and a load balancer

An API gateway is focused on routing requests to the appropriate microservice, while a load balancer is focused on distributing requests evenly across a group of backend servers.

Another difference between the two is the type of requests that they typically handle. An API gateway is typically used to handle requests for APIs, which are web-based interfaces that allow applications to interact with each other over the internet. These requests typically have a specific URL that identifies the API that the client is trying to access, and the API gateway routes the request to the appropriate microservice based on this URL. A load balancer, on the other hand, is typically used to handle requests that are sent to a single, well-known IP address, and then routes them to one of many possible backend servers based on factors such as server performance and availability.