Distributed rate limiter

A Redis-backed, token-bucket rate limiter built as a lightweight Spring Boot library. Used to protect a payments API from abusive traffic spikes across three AWS regions without adding noticeable latency to the request path.

Highlights

• —Cut abusive-traffic incidents by over 90% in the first quarter after rollout
• —Sub-2ms overhead per request at p99 under production load
• —Packaged as an internal library reused by four other services