@benjaomingBenjamin Balder Bach
@pauloxPaolo Melchiorre To be honest I don't know how scalable Mattermost is, but Golang and PostgreSQL sound like green flags. The cloud version seems to target enterprise though, so probably at a high cost.
It seems fully open-source, from the server (which is self-hostable) to desktop and mobile apps. Probably the cloud version has closed-source extensions but I don't know which features it offers.
