Introduction
What Is the Token Bucket Algorithm?
Real-World Scenario: Stopping a Credential-Stuffing Attack on a Banking API
How Token Bucket Protects Your API Gateway
Complete, Error-Free Python Implementation
Integration with a Flask API Gateway
Best Practices for Production Deployment
Conclusion
Introduction
Your API gateway is the front door to your entire digital ecosystem. If left unprotected, it becomes a magnet for bots, scrapers, and attackers. One of the most effective—and elegant—ways to defend it is the token bucket algorithm, a rate-limiting strategy that balances fairness, burst tolerance, and simplicity.
In this article, you’ll implement a production-ready token bucket rate limiter in Python and see how it stopped a live credential-stuffing attack on a major banking API—without blocking legitimate users.