Implementing Token Bucket Rate Limiting for High-Volume Inventory APIs
The article addresses the need for rate limiting in inventory and checkout APIs exposed to public front-ends or third-party webhooks. It highlights a common mistake: using a fixed window counter (e.g., 100 requests per minute resetting at the minute mark). This allows attackers to double burst traffic by sending 100 requests at 11:59:59 and another 100 at 12:00:01, overwhelming the database. The recommended solution is the token bucket algorithm, which maintains a bucket with a maximum token capacity. Tokens are added at a constant rate over time, and each request consumes one token. When the bucket is empty, requests are rejected with HTTP 429 Too Many Requests. This approach handles uneven burst traffic safely without crashing the database, ensuring consistent API performance under load.
Token bucket rate limiting prevents API abuse and database overload from burst traffic.