Implementing API Rate Limiting and Throttling

When to Use

• Protecting authentication endpoints against brute force and credential stuffing attacks
• Preventing API abuse and resource exhaustion from automated scripts and bots
• Implementing fair usage quotas for different API consumer tiers (free, premium, enterprise)
• Defending against denial-of-service attacks at the application layer
• Meeting compliance requirements that mandate API abuse prevention controls

Do not use rate limiting as the sole defense against attacks. Combine with authentication, authorization, and WAF rules.

Prerequisites

• Redis 6.0+ for distributed rate limit counters (or in-memory for single-instance deployments)
• API framework (Express.js, FastAPI, Spring Boot, or Django REST Framework)
• Monitoring system for rate limit metrics (Prometheus, CloudWatch, Datadog)
• Understanding of the API's normal traffic patterns and peak usage
• Load testing tool (k6, Gatling, or Locust) for validating rate limit behavior

Workflow

Step 1: Rate Limiting Strategy Design

Define rate limits per endpoint category and user tier:

# Rate limit configuration
RATE_LIMITS = {
    # Authenti…