Rate Limiter Algorithms

A rate limiting library that provides various algorithms and works in any Javascript environment.
You can find more information about algorithms in this article.

Example with Node.js

1import { createServer } from "node:http";
2import { RateLimiter } from "rate-limiter-algorithms";
3
4const limiter = new RateLimiter({
5    algorithm: "token-bucket",
6    limit: 5,
7    windowMs: 5000,
8});
9
10const server = createServer(async (req, res) => {
11    const uniqueKey = req.socket.remoteAddress; // or any other unique key like userId
12
13    try {
14        const { isAllowed, clientData } = await limiter.consume(uniqueKey);
15
16        // set rate limiting headers
17        const headers = limiter.getHeaders(clientData);
18        for (const header of headers) {
19            res.setHeader(header[0], header[1]);
20        }
21
22        if (!isAllowed) {
23            res.writeHead(429, "Too many requests");
24            res.end("Failure");
25            return;
26        }
27        res.end("Success");
28    } catch (error) {
29        console.error("Error in rate limiting:", error);
30    }
31});
32
33server.listen(3000, "127.0.0.1", () => {
34    console.log("Listening on 127.0.0.1:3000");
35});

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

Memory Store

Default in-memory option. Example:

1import { RateLimiter, MemoryStore } from "rate-limiter-algorithms";
2
3const limiter = new RateLimiter({
4    algorithm: "token-bucket",
5    limit: 5,
6    windowMs: 5000,
7    store: new MemoryStore(), // defaults to this value if unspecified
8});

Redis Store

Uses rawCall function to send raw commands to Redis. Example for node-redis :

1import { RateLimiter, RedisStore } from "rate-limiter-algorithms";
2import { createClient } from "redis";
3
4const client = createClient();
5client.connect();
6
7const limiter = new RateLimiter({
8    algorithm: "token-bucket",
9    limit: 5,
10    windowMs: 5000,
11    store: new RedisStore({
12        prefix: "rla:", // defaults to this value if unspecified
13        rawCall: (...args: string[]) => client.sendCommand(args),
14    }),,
15});

Raw command list:

Library	Function
node-redis	(...args: string[]) => client.sendCommand(args)
ioredis	(command: string, ...args: string[]) => client.call(command, ...args)

License

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