I saw no mention of these Slack alternatives (all Open-Source): * Matrix (https://matrix.org https://matrix.org) * Mastodon (https://joinmastodon.org/ https:/

I saw no mention of these Slack alternatives (all Open-Source): * Matrix (https://matrix.org https://matrix.org) * Mastodon (https://joinmastodon.org/ https://joinmastodon.org/) Both could be put to use as a Slack alternative, but lack a number of the bells and whistles that make Slack an easy experience. Mastodon in particular I could see replacing Slack, if it became more polished and they made an organization-centric version/mode of their UI.