What is your best tools for chat with your team?

If I have a choice IRC. It lets me get my work done and ignore chat unless absolutely needed.

• It is extremely customizable
• Can choose preferred client or cli
• It has built-in communication protocol (i.e. ping/pong for back and forward or q&a)
• Filters messages to specific windows/buffers/logs

I have also used MS Teams, slack, and discord (yes other than for gaming). I think they're all pretty good. Thought, I'd rate slack the lowest only due to lack of native dark theme (don't feel like spending hours editing css every update.)

Slack is probably the most common tool because its popularity. Everybody knows it thus easier to integrate.
My favourite is Telegram, but it's not convenient for big teams.

We use RocketChat for our chat communication. So far it has remained my favorite.