API Gateway vs. Load Balancer: What's The Difference?

You may have heard of a load balancer and an API gateway, but do you know what sets them apart? Both are essential components of web infrastructure architecture, yet their differences can be confusing for those who don't work in technology.

Think about it this way: the load balancer is like a ticket booth operator at a major theme park, and the API gateway is like a turnstile located near the entrance. They both manage traffic coming into your website or application; however, they have different roles in managing this traffic.

In this blog post, we'll identify how each gateway works differently so that you can better understand which option best suits your business needs.

API Gateway Overview

An API gateway is an intermediary between the client and the server. It is a single entry point for multiple services within your web or mobile application. You can think of it as a gatekeeper that manages access to your backend services, such as databases, microservices, functions, etc.

The main purpose of an API gateway is to provide a secure and consistent access layer for client applications. It can also perform various tasks, like rate-limiting requests, authenticating users, logging requests/responses, enforcing security policies, etc.

API Gateway Functions

The API gateway can provide many functions. Here are a few of the main ones:

• Authentication – Authenticates incoming requests and verifies if the user has access to those resources.
• Authorization - Controls what data or services the user is allowed to access.
• Rate Limiting - Limits the number of requests that can be made within a certain time frame.
• Logging - Logs requests and responses to help with troubleshooting, debugging, and auditing.

These functions help ensure that only authorized users can access the resources they need and prevent malicious actors from overloading your system.

API Gateway Use Cases

API gateways are typically used in web/mobile applications, where there may be multiple services or APIs that need to be integrated. It helps simplify the process of securely accessing and integrating these services into one easily accessible interface.

For example, suppose you have an eCommerce website with multiple microservices that handle tasks differently (such as product catalog, orders, payments, shipping, etc.). In that case, an API gateway could provide a single entry point for all these services.

Load Balancer Overview

A load balancer is a service that distributes incoming traffic across multiple servers or resources. In most cases, it sits in front of two or more web servers and distributes network traffic between them. This helps ensure the optimal utilization of server resources and efficient content delivery to the user’s device.

In essence, a load balancer API ensures that requests are sent to the right server at the right time — effectively alleviating strain on any server by evenly distributing requests.

Load Balancer Functions

The primary role of a load balancer is to balance the load between two or more servers. It does this by monitoring the health of its backend servers and distributing traffic accordingly.

In addition, a load balancer can also provide other important functions, such as:

• SSL Offloading – Takes responsibility for managing encryption/decryption of HTTPS traffic.
• HTTP Compression – Compresses web pages to reduce the amount of data sent over the network.
• Content Caching – Stores frequently used content in a cache, so it can be quickly retrieved when needed.

Load Balancer Use Cases

Load balancers are commonly used in applications that require high availability, scalability and/or redundancy. Examples of use cases include:

• Distributing load across multiple web servers to improve performance
• Providing high availability for critical applications such as e-commerce websites
• Allowing for server redundancy in the event of downtime

Now that we've identified some everyday use cases for API gateways and load balancers, let's compare them.

Comparison: API Gateway vs. Load Balancer

So, how do API gateways and load balancers differ? The main difference between these two services is that API gateways provide secure access to backend services, whereas load balancers distribute traffic between multiple servers. In short, a load balancer API distributes incoming requests while an API gateway authenticates and provides access to data sources or other applications.

When deciding which option is best suited for your application, you'll need to consider the following factors:

• Functionality - Does your application need authentication or rate-limiting? If so, an API gateway may be the better choice.
• Performance – How many loads will your application be expected to handle? A load balancer may be the better option if you need to distribute traffic across multiple servers.
• Cost – API gateways are generally more expensive than load balancers, so budget is also a factor to consider.

Summary of API Gateway and Load Balancer

An API gateway vs. load balancer comparison can be boiled down to the fact that they both manage traffic entering your website or application but have different roles. An API gateway handles authentication and security policies, while a load balancer API distributes network traffic across multiple servers. When selecting a gateway for your application, consider which one best meets your specific security and performance needs.

With this information in mind, you can make a more informed decision when selecting an API gateway or load balancer for your application.