Rate limiting protects infrastructure from traffic surges, malicious scraper bots, and denial of service attacks while ensuring fair usage across API tenants.
1. Comparing Rate Limiting Algorithms
| Algorithm | Burst Capacity | Memory Footprint | Best Suited Use Case |
|---|---|---|---|
| Token Bucket | Supports bursts up to bucket size | Low (tokens count + timestamp) | General public API rate limiting |
| Leaky Bucket | Smooths out bursts into steady queue | Medium (FIFO queue buffer) | Traffic shaping for downstream microservices |
| Sliding Window Log | Zero burst boundary window bugs | High (Stores timestamp per request) | High-security financial transaction endpoints |
| Sliding Window Counter | High accuracy with fast computation | Low (Current + previous window counters) | High-scale API Gateways (Envoy, Kong, Cloudflare) |
Rate Limiting Algorithm Comparison
2. Standard Rate Limiting HTTP Headers (IETF Draft)
ratelimit-headers.http
HTTP/1.1 429 Too Many Requests
Content-Type: application/problem+json
RateLimit-Limit: 100
RateLimit-Remaining: 0
RateLimit-Reset: 1798761600
Retry-After: 30Check Rate Limit Declarations in OpenAPI
Inspect your OpenAPI specification for 429 response declarations and standard RateLimit headers using APIForge.