[vorpalhex]

NATS is amazing but note that it makes different promises than Pulsar. NATS doesn't offer true durability (in exchange for amazing performance and great simplicity) whereas Pulsar and similar are meant to survive certain partition or failure situations and not lose data.

It's not one or the other, they're just different tools.

[jjjensen90]

There is nats-streaming-server as well which offers true durability (via file or SQL store) and a streaming model very similar to Kafka and Pulsar. It can also run as a raft cluster or in fault tolerance mode. It still has very good performance and is very simple to deploy and operate (I use it for event sourcing for real time IoT data at my day job).

[manigandham]

NATS Streaming has major scalability problems even if it's simple to deploy. It's only high-availability unless you the Raft clustering but that has been bolted on to the original project and isn't really well-designed.

The team is working on an entirely new system called Jetstream to eventually replace it.