API Rate Limiting vs. API Throttling: How Are They Different? Vyom Srivastava March 8, 2023 The explosive growth of digital services and mobile devices has created new challenges for developers trying to support users with different needs and usage patterns. High user demand, limited network data plans, and user frustration all combine to create a need for API throttling. You don’t want users to get locked out of your service because you allowed them to make too many API calls too quickly. At the same time, you don’t want to leave potential customers on the sidelines because your API has rate limits in place to prevent abuse. As a developer, you must balance these two competing interests appropriately. In this article, we’ll take a detailed look at API throttling and API rate limiting, comparing how they’re similar and how they’re unique approaches to managing requests. What is API Throttling? Nowadays, web APIs are the primary way that software systems interact with one another. When you click on a link in a web browser, and another application handles the request and returns the result, it’s almost certainly handled via an API. In the simplest form of API throttling, the throttler would be part of the API server, and it would monitor the number of API requests per second and minute, per user, or per IP address based on user authentication. An API throttler can be applied to APIs at any stage of the software development lifecycle. The throttler is the mechanism that controls how quickly your application can make calls to other applications or a web service. Throttling is most commonly applied to services that use public data sources or public cloud providers like AWS. What is API Rate Limiting? Rate limiting, on the other hand, is the practice of limiting the number of requests that can be made to an API within a specific time period. It’s a defensive way to prevent bulk-use commercial customers from impacting the service and to prevent denial-of-service attacks. Most commonly, rate limiting is applied to APIs in the backend layer of a hybrid architecture. Rate limiting is a mechanism that can be used to ensure that one user does not overwhelm a system by submitting too many requests too quickly. The main difference between throttling and rate limiting is that you can throttle an individual user, but you can only rate limit an entire server. You can’t throttle a group of users. Similarities Between API Rate Limiting and API Throttling API rate limiting and throttling are two techniques used to control how often a user can access your APIs. They are common when you want to protect your system from getting overloaded by requests and protect your users from exceeding their data limits. There are several commonalities between the two: Both rate limiting and throttling are used to control the number of calls per specified period of time. Both techniques can be implemented directly on the server side using a language such as Java, Ruby, or Python. Additionally, both techniques can help prevent an API’s abuse or misuse. Limiting the number of requests that can be made makes it more difficult for malicious users to flood the system with requests and bring down the API. Differences Between API Throttling and Rate Limiting API throttling is a type of rate limiting that is used to control the amount of traffic that an API can handle. It is a way of limiting the number of requests that the API will accept in a given period of time. This method is easier to implement. Throttling is a common practice in situations where the backend of an API is constrained by network or hardware (e.g., databases or servers). In distributed systems, rate limiting is a mechanism for ensuring that a single client does not monopolize the system’s resources. It restricts how many times a user can access the API within a time frame. Rate limiting is important because it protects the API from being exhausted by a single user. Setting up a fine-grained rate limit is important to establish more predictable traffic patterns. Common Mistake: Misunderstanding Throttling and Rate Limiting It is easy to confuse throttling vs. rate limiting. They are similar, and both are mechanisms for controlling traffic in software systems. But confusion between the two could lead to mistakes in the development process. API throttling is the practice of slowing down API calls to prevent the overload of your servers or other systems. This can be done manually by taking the server offline or by inserting a delay in the API call to prevent the overloading of your servers or other systems. Thus, API throttling is implemented directly on the server side using a language such as Java, Ruby, or Python. On the other hand, rate limiting is done on a user or client level. And although it does offer more granular control over the API’s usage access, it is harder to implement when treating the problem as a server-level problem. Does the Difference Matter? Yes. This is one of the main differences between rate limiting and throttling. And it is often the deciding factor in whether to apply throttling or rate limiting. Throttling can be used to control the flow of data from a device to a server. This is a great way to prevent a single user from exhausting their bandwidth or gobbling up too much processing power. But, it doesn’t make sense for a single user in a hybrid architecture to throttle other users’ requests to the server, and it doesn’t make sense to throttle another customer’s request to the server. When To Implement API Rate Limiting vs. API Throttling There are a few key factors to consider when deciding whether to implement API rate limiting or API throttling. One is the type of API traffic you are dealing with: if it is bursty or steady. Another is the desired level of control over the API traffic: if you want fine-grained control or just a general idea of usage. And finally, you need to consider the impact of either solution on your API performance. If you are dealing with bursty API traffic, then rate limiting is the better solution. This is because it allows you to control the traffic on a per-second basis, which can be important for avoiding overloads. On the other hand, throttling is the better solution if you are dealing with steady API traffic. This is because it allows you to average out the traffic over a period of time, which can be important for maintaining consistent performance. As for the level of control, rate limiting gives you much finer control over the traffic, while throttling is more of a general solution. If you need to specifically limit the amount of traffic at any given time, then rate limiting is the way to go. However, if you just want to get an idea of overall usage, then throttling is sufficient. Finally, you need to consider the impact of either solution on API performance. Rate limiting can impact performance more since it requires more processing to keep track of the traffic on a per-second basis. Throttling can also impact performance, but to a lesser extent, since it only requires processing on a per-request basis. Final Words APIs play a critical role in modern software development, so it is important to manage their usage and performance. While you don’t want to prohibit customers from accessing the service, you don’t want to overwhelm your servers either. Although the differences between throttling and rate limiting may seem subtle at first, there are some important distinctions to keep in mind. The key is to recognize the source of the difference. Once you’ve identified the source, you can apply the appropriate control mechanism. With the right controls in place, you can increase customer satisfaction and manage your network traffic.