Rate Limiting Patterns: Protecting Your APIs Without Frustrating Users
Every API needs rate limiting. Without it, a single misbehaving client can overwhelm your service, intentional attacks become trivial, and cost management becomes impossible. But implement it poorly, and you’ll frustrate legitimate users while barely slowing down bad actors. Let’s explore rate limiting patterns that actually work. The Fundamentals: Why Rate Limit? Rate limiting serves multiple purposes: Protection: Prevent abuse, DDoS attacks, and runaway scripts Fairness: Ensure one client can’t monopolize resources Cost control: Limit expensive operations (API calls, LLM tokens, etc.) Stability: Maintain consistent performance under load Algorithm 1: Token Bucket The token bucket is the most flexible approach. Imagine a bucket that fills with tokens at a steady rate. Each request consumes a token. If the bucket is empty, the request is denied. ...