Would you use NATS over Redis PubSub or Postgres Notify/Listen? Postgres's option I'm wary of for reasons I've discussed here before but Redis PubSub seems fairly simple to use and likewise not as uber-scalable as Kafka and other more heavyweight message broker systems.
Not the parent, but I would. We've been using NATS for about five years at my company, and we recently adopted JetStream, and have been really impressed with it.
NATS, especially with JetStream now, is a Swiss Army knife of messaging. It can do RPC, Kafka-type batch streaming, low-latency realtime notifications, large-scale network transfer, offline sync, work queues, mirroring, weighted routing, partitioning... it's incredibly flexible. The simple but powerful primitive you have around subject routing/mapping/transforms, stream placement, replication, offline lead nodes etc. are just fantastic. It's super reliable. It scales from tiny apps to huge ones. The CLI and API tooling around streams and consumers is also fantastic.
Everything just feels well-designed and sensible. The new key/value store and blob store (both built on top of JetStream as client-side abstractions) are also super neat, and we've started using this functionality.
Yes, and no issues at all. We run superclusters with a bunch of nodes, and the Raft-based leader election system has worked flawlessly so far (knock on wood!).
Keep in mind that NATS does not yet support value operations other than setting the whole value. Optimistic locking is supported, but NATS does not have inc/decrement, append, set members, etc. I believe such support is on the horizon, however.
I would probably use NATS just because I’m more familiar. I love redis but I’m fairly skeptical when my database starts wanting to be my message broker
