Introduction

RateLock is a rate limiting library for Node.js and Bun with per-engine implementations.

Why RateLock?

Most rate limiting libraries use a single backend abstraction. RateLock implements each engine natively:

• Redis uses Lua scripts for atomicity
• PostgreSQL uses UPSERTs for consistency
• In-Memory uses Maps for zero-overhead single-process apps

Features

• 4 rate limiting strategies: Fixed Window, Sliding Window, Token Bucket, Individual Fixed Window
• 3 storage engines: In-Memory, Redis, PostgreSQL
• Built-in resilience: Retry with backoff, circuit breaker, fallback policies, deny cache
• TypeScript first: No any leaks, strict config types
• Dual driver support: Redis (node-redis or ioredis), PostgreSQL (pg or porsager/postgres)
• Batch operations: Check multiple identifiers in a single call

Quick Example

import { fixedWindow } from '@ratelock/local'

const limiter = await fixedWindow({
    limit: 100,
    windowMs: 60_000, // 100 requests per minute
})

const result = await limiter.check('user:123')

if (!result.allowed) {
    return new Response('Too Many Requests', { status: 429 })
}

Next Steps

• Install RateLock
• Quick Start guide
• Explore rate limiting strategies
• Choose a storage engine
• Read about resilience policies