Design a Rate Limiter - Protecting APIs at Scale

Public lesson preview

Learn how to design a distributed rate limiter using token bucket, sliding window, and Redis-backed algorithms to protect APIs from abuse and ensure fair usage.

Learning objectives

By the end of this lesson, you will understand:

• ✓Step 1 - Requirements Gathering
• ✓Step 2 - Rate Limiting Algorithms
• ✓Step 3 - High-Level Architecture
• ✓Step 4 - Deep Dive: Distributed Rate Limiting
• ✓Step 5 - Handling Edge Cases

Lesson outline

1. Step 1 - Requirements Gathering
2. Functional Requirements
3. Non-Functional Requirements
4. Step 2 - Rate Limiting Algorithms
5. Fixed Window Counter
6. Sliding Window Log
7. Sliding Window Counter
8. Token Bucket Algorithm (Most Popular)
9. Algorithm Comparison
10. Step 3 - High-Level Architecture
11. Where to Place the Rate Limiter
12. Step 4 - Deep Dive: Distributed Rate Limiting
13. Redis + Lua Scripts
14. Response Headers
15. Step 5 - Handling Edge Cases
16. Race Conditions
17. Rate Limiting Dimensions
18. Distributed Clock Skew
19. Step 6 - Bottlenecks and Optimisations
20. 📚 Further Reading