Reverse Proxy vs Load Balancer vs API Gateway: Key Differences

Optimizing online data routes is becoming necessary for numerous businesses that rely on digital information. News sites, e-shops, marketing agencies, and dozens of other modern enterprises run websites heavy with traffic, and the more they grow, the slower websites can become.

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Reverse proxies can also act like load balancers. However, load balancers' primary focus is on redistributing traffic across a server network to make it faster; meanwhile, reverse proxies act as a single point of entry. They can cache content to save server resources, decrease website loading time, and compress data to minimize bandwidth consumption. They can also perform SSL termination so that backend servers don't have to, ensuring their continuous performance.

How Reverse Proxies Work

Whenever clients (usually web browsers) make HTTP requests, reverse proxies intercept and reroute them to selected backend servers. Here's a concise step-by-step process description:

1. A client makes an HTTP request to a reverse proxy server using its IP address.


2. The reverse proxy inspects the request and, depending on its configuration, sends it to the correct backend server. At this point, it can also perform SSL termination or retrieve cached data.


3. The backend server fetches the requested information and sends it back to the reverse proxy server.


4. In this step, the reverse proxy may perform additional tasks like data compression.


5. The final response is sent to the client.
   

The logic is straightforward enough, but reverse proxies get more complex with each additional feature. Optimized load balancing algorithms and SSL termination require close attention to prevent server downtime and cybersecurity risks.

Benefits

The essential reverse proxy benefits can be summarized in two broad categories: cybersecurity and load balancing. Let's start with the first.

Cybersecurity

Providing direct access to backend servers poses risks like DDoS takedown,

Just like reverse proxies, API gateways also function like a single point of entry to access backend resources. But as you might have guessed, API gateways focus on API traffic. Whenever a client interacts with a large application, it uses multiple smaller services that all have their APIs. Managing them independently is tedious and inefficient, so API gateways simplify the process by mediating API traffic.

How API Gateways Work?

API gateways work very similarly to reverse proxy servers, but they have features optimized for API traffic management in microservice systems. Here's a simplified API gateway workflow.

1. API gateways stand between clients and backend services in microservice systems. Instead of interacting with multiple backend services, clients make requests to a simplified API gateway.


2. API gateway accepts and interprets client API requests and transmits them to correct backend microservices.
   


3. At this point, an API gateway can make modifications based on established requirements, like load balancing between backend resources, caching, authentication, and rate limiting. API gateways can also perform encryption and decryption to secure data exchanges.


4. Lastly, API Gateway performs API versioning to add new features or remove deprecated ones without causing service downtime. It also collects valuable information for solving errors and stores helpful documentation for developers.

Benefits

API gateways offer several benefits that are crucial to smooth microservice functioning. They are particularly useful in simplifying client interaction, enabling developers to efficiently manage large systems. Let's take a closer look.

Load Balancing and Caching

Similar to the other two technologies discussed in this article, API gateways also assist with data routing optimization. In this case, an API gateway redistributes client requests among various backend services, providing a single point of entry.

It reroutes requests to backend services that have sufficient resources, ensuring system stability by preventing downtime and overloading. Simultaneously, API gateways also cache frequently used data to prevent unnecessary resource waste.

Rate Limiting

API gateways are widely used, and they receive a lot of client requests due to their popularity. Malicious actors also exploit insecure APIs to take down selected services, similar to DDoS attacks. This can put a significant strain on an API gateway, which is mitigated using rate limiting.

It ensures that each client has a fair chance of accessing required backend services, and no one can flood the API gateway to make it slower or take it down. Rate limiting ensures the high availability of the microservice system.

Cybersecurity

API gateways efficiently protect against DDoS, but they also provide client authentication via API keys or other methods. They can also revoke API keys to prevent unauthorized access. Like a reverse proxy, an API gateway can perform traffic encryption and decryption to protect API traffic from tampering and surveillance. Lastly, it monitors and logs suspicious activity to detect threats and inform responsible parties about the incident.

Use Cases

You will encounter API gateways in most programs and services that incorporate multi-function elements. For example, a food ordering app that has a payment processor uses an API to establish communication between two separate programs. The more features and multi-function elements the selected service has, the more critical the API gateway becomes for smooth and secure functioning.

This technology is particularly popular among Internet of Things (IoT) devices. Their high variety demands cross-system communication, and API gateways have the ability to 'translate' between different data exchange protocols (like HTTP, MQTT, DSP, etc.) to connect them into one cohesive system.

What Is a Load Balancer?

Load balancers are the most straightforward on this list. As the name implies, a load balancer is designed to redistribute traffic between multiple backend servers. It ensures high availability by routing traffic to servers that have the most open connections, are geographically closer or will respond faster, depending on load balancer configuration.

Although load balancers can be configured to perform additional tasks, like SSL termination, it is uncommon. They are primarily used to balance online data flows, identify underperforming servers, and reroute traffic to the best ones. Load balancers are essential for website scaling, as they assist in adding new servers to a broader network.

How Load Balancers Work?

The load balancer's primary task is to accept client requests and send them to the correct server. Here is a typical workflow of a load balancer that is not modified to perform any additional features found on a reverse proxy or an API gateway.

1. A load balancer accepts client requests, which can be web browsers, other applications, etc.


2. According to its configuration, it selects the correct server and reroutes the request to it.


3. The server fetches the required information and sends it back to the load balancer, which forwards it to the client.
   

The process is much more straightforward compared to a reverse proxy or an API gateway, but that doesn't mean it lacks customization freedom.

One of the most significant load balancer benefits is flexible routing algorithms. The simplest round robin algorithm distributes traffic circularly among server networks, which can be switched to last connections algorithm to send requests to the least overloaded server.

Load balancers can prioritize servers with the least response time or always send selected client data to the same server. There are numerous possible options depending on each client's needs.

Benefits And Use Cases

Load balancers ensure high availability by maintaining server uptime. To achieve that, a load balancer can perform a server health check. Typically, they perform TCP and HTTP(S) protocol connection checks or ping a selected server to mark down its status. It's worth noting that these checks are also customizable so that load balancers can work with a variety of servers.

Load balancers are highly popular in the contemporary digital landscape. The internet has become an invaluable conversion channel in a broad sense, and most enterprises establish websites if they want to grow. Each growing website demands more servers to remain fast and available, so a load balancer is popular among all companies that do some of their business online.

Reverse Proxy vs Load Balancer vs API Gateway: Key Differences

Although all three technologies have apparent differences, they are still designed to optimize online data flows. Take a look at the table below for a direct comparison.

Final Thoughts

With billions of internet users worldwide, maintaining a speedy and secure infrastructure is challenging. All three discussed technologies play a crucial role in this task, whether by routing API requests, providing single entry point gateways, or saving server resources with load balancers. Whichever one you require depends on your specific needs, but you can also find all three in one system.