Queues

Queues gives Workers a native way to decouple work: push messages from a producer, consume them in batches with automatic retries and dead-letter queues. For the classic “do this expensive thing later” pattern, it’s pleasant and cheap, and the DX of a queue being just another binding is exactly right.

The limitations define its ceiling. Throughput caps per queue mean you architect around sharding early, there are no ordering guarantees (no FIFO), and delivery is at-least-once with the duplicate handling left to you. It’s also built on Durable Objects, which given my experience elsewhere on this list is not a confidence booster for the tail-latency and availability story.

It’s a happy fit for webhooks, notifications, and background processing where a delayed or duplicate message is harmless. I would not put it at the center of an event-driven architecture yet.