I think that's a bit unfair to Slack. I've been using it for 5 years now and it's one of the most dependable apps I've ever used. When you consider how many messages and rich content it's handling, I think they are doing a fairly decent job. I wouldn't call it slow either. If anything my biggest beef with slack is sometimes the cross-device syncing isn't perfect. And I'm unable to use it offline at all.

I am also a daily user, because it is part of my job requirements to be accessible via Slack, as such it only has a presence on the devices that belong to my employer.

> When you consider how many messages and rich content it's handling, I think they are doing a fairly decent job.

"handling"

Sending and receiving is something for a background thread to spend a fraction of a percent of a CPU core on.

The amount on-screen at any time is tiny, and should not take a significant amount of resources on a modern computer.

If it's rendering a thousand off-screen rich content messages, that's not impressive, that's it being coded badly.

Slack is hands down the worst app I’ve ever used in environments that aren’t very high latency.