Queues vs Streams vs Event Bus: The Mental Model That Makes System Design Click

Short summary

Queues, streams, and event buses are three distinct architectural patterns often confused because they look similar on diagrams. Queues delete after single consumption; streams maintain offsets for independent consumer speeds; event buses route events via rules. Mastering these mental models unlocks better system scaling decisions.

• •Queues are to-do lists: one job, one consumer, deleted after processing
• •Streams are rewindable logs: consumers independently track position via offset
• •Event buses are switchboards: events trigger reactions via predefined rules without hardcoded wiring

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