What is the best opensource alternative to Slack in your view? With bot/open api!

Of course Telegram, IMHO! 🙂 I’ve started discussing projects, etc with teams and related parties on it.

I know Telegram is great and I know its free... Why I didn't think about it? Thanks.

Sorry Zaheer, I missed the first sentence. Should be read more carefully. 🙏🏻

Thanks! I found out that Bitnami has a VM for both Mattermost and LetsChat.. so will try them out.