Distributed rate limiter with HRW in Elixir

A practical guide to building a cluster-aware rate limiter in Elixir without Redis, using HRW (Highest Random Weight / Rendezvous Hashing) to route rate limit checks to the correct node. The approach uses the Hammer library with an ETS backend and a GenServer that delegates requests to the node responsible for a given key. HRW is presented as a simpler, stateless alternative to ExHashRing for small clusters (under 10 nodes), with minimal key reassignment when nodes join or leave. The pattern generalizes to distributed caching and ephemeral event tracking as well.