I built an in-memory rate limiter in a Next.js project

Summary

An API rate limiter is a server-side component of a web service that limits the number of API requests a client can make to an endpoint within a period of time. For example, X (formerly known as Twitter) limits the number of tweets that a specific user can make to three hundred every three hours. Rate limiters enforce the responsible use of APIs by blocking requests that exceed the set usage limits. By following along with this article, you will: Learn how rate limiters work Build an in-memory rate limiter for a Next.js app router project Use Artillery to load test the rate limiter for accuracy and resilience Here’s What We’ll Cover: Benefits of Rate Limiters How Rate Limiters Work Rate Limiting Algorithms How to Build an In-Memory Rate Limiter The Front End How to Load Test the Rate Limiter for Resilience with Artillery Conclusion To get the most out of this article, you should have experience in building APIs with Next.js app router, Express, or any other Node.js backend framework that uses middlewares. Benefits of Rate Limiters Rate limiters control how many requests are allowed within a given time window. They have several benefits you know know about if you’re considering using them. First, they help prevent the abuse of web servers. Rate limiters guard web servers from overuse that needlessly increases their load. They block excessive requests from Denial of Service (DoS) attacks from bots so that the web service doesn’t crash from unnecessary overload and can continue to be available to legitimate users. They also help manage the cost of using external APIs. Some API endpoints make requests to external APIs to complete their operations – for example, API endpoints that send emails through an email service provider. When an endpoint relies on paid external APIs and user access of the endpoint is not restricted, excessive usage can lead to increased and expensive costs for the web service. Rate limiters block the excessive usage of endpoints like these, helping...