A weekly look at the lesser-known parts of Effect, one module at a timehttps://effect.website/https://effect.website/blog/module-of-the-week/cluster-idempotency/https://effect.website/blog/module-of-the-week/cluster-idempotency/We look at idempotency and the dual-write problem, then use idempotency keys and transactions to safely handle messages that arrive more than once.Mon, 19 Oct 2026 00:00:00 GMTMaxwell Brownhttps://effect.website/blog/module-of-the-week/cluster-delivery/https://effect.website/blog/module-of-the-week/cluster-delivery/We look at at-most-once and at-least-once delivery, then use persisted messages to stop Dad losing messages when a runner crashes.Mon, 12 Oct 2026 00:00:00 GMTMaxwell Brownhttps://effect.website/blog/module-of-the-week/cluster-messaging/https://effect.website/blog/module-of-the-week/cluster-messaging/We write our first entity, then follow one of its messages across a cluster to see how runners agree on who owns what.Mon, 05 Oct 2026 00:00:00 GMTMaxwell Brownhttps://effect.website/blog/module-of-the-week/cluster-actors/https://effect.website/blog/module-of-the-week/cluster-actors/The first in a series on Effect Cluster. We look at the actor model and how a cluster is laid out.Mon, 28 Sep 2026 00:00:00 GMTMaxwell Brownhttps://effect.website/blog/module-of-the-week/rcmap/https://effect.website/blog/module-of-the-week/rcmap/Learn how RcMap uses reference counting to share scoped resources by key across consumers, with automatic cleanup, idle time to live, and capacity limits.Mon, 21 Sep 2026 00:00:00 GMTMaxwell Brownhttps://effect.website/blog/module-of-the-week/persisted-queue/https://effect.website/blog/module-of-the-week/persisted-queue/Learn how Effect's PersistedQueue handles background jobs, multiple workers, locking, and retries.Wed, 16 Sep 2026 00:00:00 GMTMaxwell Brownhttps://effect.website/blog/module-of-the-week/https://effect.website/blog/module-of-the-week/Module of the Week is a weekly blog post that explores the lesser-known parts of Effect, one module at a time.Tue, 15 Sep 2026 00:00:00 GMTMaxwell Brown