Visibility Timeouts Turn Message Delivery into a Renewable Lease
A queue consumer often needs time to perform work before it can safely acknowledge a message. Removing the message at receive time would make a consumer crash capable of losing work. Keeping it immediately available would let several consumers process the same item at once. A visibility timeout occupies the middle ground. Receiving a message makes it temporarily unavailable to competing consumers. The consumer gets a bounded interval to finish and acknowledge it. If that interval expires first, the queue can expose the message for another delivery.