An API gateway is a server that sits between your backend services and your users. It provides an abstraction layer that helps you manage the communication between clients and your services. API gateways are a single point of entry into a microservices application and they work like a reverse proxy: They receive API calls from clients, route them to the right microservice in the backend, and return aggregated responses to clients.
API Gateway use cases
While clients could make direct calls to backend services, this design quickly runs into complexities as the number of services in the application grows.
There are many different ways you can use API gateways. Here are few examples of how they are typically used:
(I) Analytics and monitoring
Since your API gateway resides between your users and your backend services, you can use it to collect detailed statistics about how your services are being used.
(ii) Manage versions
You can use an API gateway to update, add and retire services to your app without affecting your user's experience.
Unlike direct client-to-microservice communication, all client requests pass through your API gateway, which directs these requests to the new or modified services.
(iii) Rate-limiting
By configuring rate-limiting, you can protect your services against overuse or DoS attacks by limiting the number of requests that can be made to your services.
(iv) Security
You can use your API gateway to protect internal traffic by using it as a gatekeeper.
Benefits of using an API gateway
1. Decoupled API endpoints make for a smooth release
A request to an API gateway can trigger several calls group all of the responses from these different services, which provides a seamless experience for your users.
2. Offer a great user experience across client devices
An API gateway enables you to provide users with a seamless expression regardless of which device they use to access your service.
3. Improve performance
An API gateway can mitigate an issue in the backend by returning either cached or default responses to your users.
4. Keep services available with rate-limiting
With rate-limiting, you can manage API calls and protect your internal system from too much loading
5. Build protocol-rich applications
Since API gateway can translate different protocols, you can build applications with all the different protocols your services need.