nats.docs/developer/receiving/queues.md

Queue Subscriptions

Using queues, from a subscription standpoint, is super easy. The application simply includes a queue name with the subscription.

digraph g { rankdir=LR publisher [shape=box, style="rounded", label="PUB updates"]; subject [shape=circle, label="gnatsd"]; sub1 [shape=box, style="rounded", label="SUB updates workers"]; sub2 [shape=box, style="rounded", label="SUB updates workers"]; sub3 [shape=box, style="rounded", label="SUB updates workers"];

publisher -> subject [label="msgs 1,2,3"]; subject -> sub1 [label="msg 2"]; subject -> sub2 [label="msg 1"]; subject -> sub3 [label="msg 3"]; }

For example, to subscribe to the queue workers with the subject updates:

!INCLUDE "../../_examples/subscribe_queue.html"

If you run this example with the publish examples that send to updates, you will see that one of the instances gets a message while the others you run won't. But the instance that receives the message will change.