Rate Limiter Middleware (Express, TS, Fixed + Sliding Window)

A hardened Express rate limiting library

A rate limiter for Express in strict TypeScript with fixed window and sliding window algorithms, an in-memory store, standard rate-limit headers and Retry-After support.

What's included

• Fixed window — simple per-client limits
• Sliding window — precise rolling limits
• MemoryStore — with reset APIs
• Headers — RateLimit-* + Retry-After
• Custom keyGenerator — bucket by any key
• Skip / disable — flexible control
• 22 passing tests — node:test suite
• Dual CJS/ESM build — via TypeScript

Quick Start

npm install
npm run build
npm test

Stack

TypeScript strict · Express · Node.js 18+

Use cases

• Public API protection
• Login endpoint throttling
• Abuse prevention
• Learning rate limiting