[steve_adams_86]

I once worked on a chat-based system that handled load like this, and it was initially built with kafka. I worked out that the cost per message was several cents, haha. I replaced it with a redis queue, which was all I knew at the time, and it ran on a digitalocean droplet for CAD $5 per month for around 18 months before they scaled it up. It was handling ~100 messages per second peak at the end, which is still very low. The cause for concern was that the droplet silently failed due to memory issues on a particularly busy day, so it seemed reasonable to jump to the next tier to avoid that issue for a while.

For what it's worth I never intended for the 1CPU/1GB VM to go to production, but I was a consultant and they just ran with it. And it worked!

They swore off of kafka forever after the pains they had with it. Another consultant built that system for them, so it wasn't an internal decision exactly and they had no idea what they were getting into. I've heard of similar experiences since. I've sometimes hoped to land on a project where kafka was well suited to the problem, though; I learned a lot about it back then and it seemed incredibly cool. I was kind of envious of all these projects fully utilizing it!