API Gateway vs. Load Balancer vs. Reverse Proxy

Dr Milan Milanović
2 min readApr 21, 2024

API Gateways, Reverse Proxy Servers, and Load Balancers are essential components in modern software architecture. Each serves a specific role that enhances web application performance, security, and scalability. Yet, we often need clarification about the roles of those services.

Here are the main characteristics:

  • API Gateway sits between a client and a group of backend services. It performs the function of a reverse proxy by accepting all application programming interface (API) calls, aggregating the different services needed to fulfill them, and returning the right outcome. User authentication, rate limits, and statistics are typical duties that API gateways take care of on behalf of a system of API services. Also, the API gateway can handle faults (circuit breaker) and log and monitor.
  • A Load Balancer is a service that distributes incoming traffic across many servers or resources. Usually, we have two or more web servers on the backend, and it distributes network traffic between them. Its primary purpose is to use resources optimally. Equal task allocation and increased capacity can enhance the system’s responsiveness and reliability. There are three high-level load balancers: hardware-based, cloud-based, and software-based.
  • Reverse Proxy server resides in front of backend servers and transfers client requests to these servers. Reverse proxies are typically used to increase security, speed, and dependability. A reverse proxy receives a request from a client, forwards it to another server, and then returns it to the client, giving the impression that the first proxy server handled the request. These proxies ensure that users don’t access the origin server directly, giving the web server anonymity. They are usually used for Load balancing, where we need to deal with incoming traffic flow so that we may distribute that traffic between multiple backend servers or use them for caching.

So, the main thing that differs these two is that an API Gateway is focused on routing requests to the appropriate service and handles requests for APIs, while a Load Balancer is focused on distributing requests evenly between a group of servers and handles requests that are sent to a single IP address, which works at protocol or socket level (TCP, HTTP).

Some examples of API Gateways are:

Load Balancers are:

An example of reverse proxy services are:

API Gateway vs. Load Balancer vs. Reverse Proxy

Read the rest of the article, including bonus chapters in the Tech World With Milan Newsletter.

Originally published at https://newsletter.techworld-with-milan.com on April 18, 2024.

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