Rate Limit Lab

An interactive dashboard for visualizing and comparing rate-limiting algorithms in real time.

Algorithms

• Fixed Window — counts requests in fixed time intervals
• Sliding Window Log — tracks exact timestamps of each request
• Sliding Window Counter — weighted blend of current and previous window counts
• Leaky Bucket — requests drain at a constant rate from a queue
• Token Bucket — tokens refill at a steady rate; requests consume tokens

Prerequisites

• Node.js (v18+)

Getting Started

# Install dependencies
npm install

# Start the dev server
npm run dev

The dashboard will be available at http://localhost:3456.

Project Structure

server.ts              → Express server with API routes for each algorithm
public/index.html      → Single-page dashboard UI
rate-limiters/
  token-buckets.ts     → Token Bucket implementation
  fixed-window.ts      → Fixed Window implementation
  sliding-log.ts       → Sliding Window Log implementation
  sliding-counter.ts   → Sliding Window Counter implementation
  leaky-bucket.ts      → Leaky Bucket implementation
  lru-map.ts           → LRU map used for per-IP state eviction

API

Each algorithm exposes two endpoints:

Endpoint	Description
GET /api/<algorithm>/hit	Send a request through the rate limiter
GET /api/<algorithm>/status	Check current rate-limit state without consuming a token

Algorithm slugs: token-bucket, fixed-window, sliding-window-log, sliding-window-counter, leaky-bucket.