How to implement rate limiting in express app using upstash

We can use @upstash/ratelimit package to implement rate limiting. To use the @upstash/ratelimit package for rate limiting in a Node.js application, you first need to install the package and set it up correctly. Below are the steps to integrate and use the Ratelimit class from the @upstash/ratelimit package in your application.

Step-by-Step Guide

1. Install the Package:

   Make sure you have Node.js and npm installed. You can install the @upstash/ratelimit package using npm or yarn:

   npm install @upstash/ratelimit
   # or
   yarn add @upstash/ratelimit
   

2. Import and Configure the Ratelimit Class:

   Create a file (e.g., rateLimiter.js) to configure your rate limiter. Here’s an example configuration using the @upstash/ratelimit package:

   // rateLimiter.js
   import { Ratelimit } from '@upstash/ratelimit'
   import { Redis } from '@upstash/redis'
   
   // Initialize Redis client
   const redis = new Redis({
     url: 'your-upstash-redis-url',
     token: 'your-upstash-redis-token',
   });
   
   // Initialize the Ratelimit instance
   const rateLimit = new Ratelimit({
     redis,
     limiter: Ratelimit.slidingWindow(10, '1m'), // 10 requests per minute
     prefix: 'my-rate-limit', // Prefix for the rate limit keys in Redis
   });
   
   export default rateLimit;
   

3. Use the Rate Limiter in Your Application:

   Integrate the rate limiter in your application, such as in an Express.js middleware. Here’s an example:

   // server.js
   import express from 'express';
   import rateLimit from './rateLimiter';
   
   const app = express();
   
   const rateLimiterMiddleware = async (req, res, next) => {
     const identifier = req.ip; // Use IP address as the identifier
   
     const { success, remaining, reset } = await rateLimit.limit(identifier);
   
     res.set('X-RateLimit-Limit', '10');
     res.set('X-RateLimit-Remaining', remaining.toString());
     res.set('X-RateLimit-Reset', reset.toString());
   
     if (!success) {
       res.status(429).send('Too many requests - try again later');
       return;
     }
   
     next();
   };
   
   app.use(rateLimiterMiddleware);
   
   app.get('/', (req, res) => {
     res.send('Hello, world!');
   });
   
   const PORT = process.env.PORT || 3000;
   app.listen(PORT, () => {
     console.log(`Server is running on port ${PORT}`);
   });
   

Explanation

• Redis Initialization: The Redis client from @upstash/redis is used to connect to your Upstash Redis instance.
• Ratelimit Configuration: The Ratelimit class is configured to use a sliding window rate limiting strategy, allowing 10 requests per minute per identifier (e.g., IP address).
• Middleware Integration: The middleware checks the rate limit for each incoming request based on the client's IP address. If the rate limit is exceeded, it returns a 429 Too Many Requests response. Otherwise, it proceeds to the next middleware or route handler.

Upstash Credentials

Replace 'your-upstash-redis-url' and 'your-upstash-redis-token' with your actual Upstash Redis URL and token, which you can obtain from your Upstash dashboard.