@jfungus/ratelimit

Framework-agnostic rate limiting library with sliding window algorithm. Zero dependencies.

Installation

npm install @jfungus/ratelimit

Usage

import { RateLimiter, MemoryStore } from "@jfungus/ratelimit";

const store = new MemoryStore();
store.init(60 * 1000); // 1 minute window

const limiter = new RateLimiter({
  limit: 100,
  windowMs: 60 * 1000, // 1 minute
  store,
});

// Check rate limit
const result = await limiter.check("user-123");

if (!result.allowed) {
  console.log(`Rate limited. Retry after ${result.retryAfter}ms`);
}

Algorithms

Sliding Window (default)

Cloudflare-style weighted sliding window for smoother rate limiting:

const limiter = new RateLimiter({
  algorithm: "sliding-window",
  limit: 100,
  windowMs: 60 * 1000, // 1 minute
  store,
});

Fixed Window

Simple counter that resets at fixed intervals:

const limiter = new RateLimiter({
  algorithm: "fixed-window",
  limit: 100,
  windowMs: 60 * 1000, // 1 minute
  store,
});

Framework Middleware

For framework-specific middleware, see:

• @jfungus/ratelimit-hono - Hono
• @jfungus/ratelimit-express - Express
• @jfungus/ratelimit-h3 - H3/Nitro
• @jfungus/ratelimit-nuxt - Nuxt

Documentation

Full documentation

License

MIT