redis-cell: a Rate Limiting Redis Module

Brandur Leach, author of redis-cell and winner of the Redis Modules Hackathon, presents a guest post explaining the development of this efficient rate limiter implementation. The module is designed to protect web services from activity spikes by controlling the rate at which users access resources. It uses a variation of the drip bucket algorithm called generic cell rate algorithm (GCRA) and exposes a single command: CL.THROTTLE. Notably, redis-cell is written in Rust due to its memory safety features and strong type system, ensuring that contributors to the project are less likely to introduce low-level problems.