Worker Rate Limiter

Worker Rate Limiter is a small package for Cloudflare Workers that enables you to Rate Limit API Requests right on the Edge. It doesn't use any 3rd-Party Database Solutions, instead it uses Durable Objects. It's also cheaper then the alternatives.

Features

• Super lightweight (~1KB)
• No external Dependencies
• Uses only Cloudflare Products
• Very Cheap

Install

npm install --save worker-rate-limiter

Usage

Export the Object and register the Durable Object in your wrangler.toml and bindings (Don't forget the migrations!)

export { WorkerRateLimitDurableObject } from 'worker-rate-limiter';

Import RateLimter and initialize it with the Durable Object from above. Add the limit Function to different Routes, Groups, etc.

import { RateLimiter } from 'worker-rate-limit';

const rateLimiter = new RateLimiter(durable_object_instance);

const blocked = await rateLimiter.limit({
  do_name: ip,
  identifier: url,
  limit: 10,
  windowMs: 5000,
});

rateLimiter.limit options

• do_name: Uniquie Durable Object Name per User like (IP, User Id, API Key, etc.)
• identifier: The Route, Group, Key that will be limited
• limit: Amount of Requests allowed in the given Window
• windowMs: Time in ms till the window resets

Todo

• Cache blocked Requests in the Worker
• Add Cron Trigger to clean the Storage
• Add multiple blocking Strategies
• Add an overall Limit
• Refactor / Optimize Code
• Add Benchmarks and Monitor Code
• Unit-Tests
• Make the Durable Object scaleable

Price Calculation

Rate Limits with a time window smaller then 30s (30000ms) are much cheaper.

• 1 million Requests (Rate Limit < 30s) should cost around ~0.16$
• 1 million Requests (Rate Limit > 30s) should cost around ~1.25$

The Default Worker Price isn't included.

Current Limitations

Arround ~100 Requests/s per unique do_name. Can be increased by creating multiple DO's for different Routes, but you shouldn't overdo it like every Route is an identifier. At some point it will have an negative affect.