Rate Limiter Algorithms

Library that provides different algorithms to perform rate limiting.

Example with Node.js

import { createServer } from "node:http";
import RateLimiter from "rate-limiter-algorithms";

const limiter = new RateLimiter({
    algorithm: "token-bucket",
    limit: 5,
    windowMs: 5000,
});

const server = createServer(async (req, res) => {
    const ip = req.socket.remoteAddress || "any unique key";

    try {
        const { isAllowed, clientData } = await limiter.consume(ip);

        // set rate limiting headers
        const headers = limiter.getHeaders(clientData);
        for (const header of headers) {
            res.setHeader(header[0], header[1]);
        }

        if (!isAllowed) {
            res.writeHead(429, "Too many requests");
            res.end("Failure");
            return;
        }
        res.end("Success");
    } catch (error) {
        console.error("Error in rate limiting:", error);
    }
});

server.listen(3000, "127.0.0.1", () => {
    console.log("Listening on 127.0.0.1:3000");
});

Config

Option	Type	Explanation
algorithm	string	Values: token-bucket, fixed-window-counter, sliding-window-logs, sliding-window-counter
windowMs	number	Duration of time in milliseconds when algorithm updates its counter.
limit	number	Maximum amount of points that client can consume
store	Store	Store which contains clients data based on chosen algorithm. Defaults to Memory Store

Date Stores

The rate limiter comes with a built-in memory store. Any store can be used that follows the same interface

License

All code and documentation are (c) 2024 Eugene Shumilin and released under the MIT License