Rate Limiting Your Next.js App with Vercel Edge

Implementing rate limiting in web applications using Vercel Edge Middleware and the @upstash/ratelimit library offers a robust solution for managing traffic efficiently. Vercel Edge, by executing computations closest to the user, minimizes latency and reduces overhead without cold start issues, making it ideal for rate limiting as it intercepts requests before they reach the backend, providing a cost-effective alternative to serverless functions. The @upstash/ratelimit library is specifically designed for edge functions and utilizes Upstash Redis for storing and managing rate limit data, supporting multi-region setups for optimal performance. The article details the setup process, including creating a Redis database and configuring a Next.js application with middleware to enforce rate limits using the sliding window algorithm, allowing only a set number of requests per IP within a specified timeframe. Additionally, caching within the @upstash/ratelimit package reduces remote calls by storing data locally when the edge function is "hot," enhancing efficiency.