I’ve not heard of getstream. Is your service open source and all data easily extracted?
This post serves as a cautionary tale about how privately owned walled gardens, no matter how pretty, leave you in a precarious position. I suspect being in control of their data and having an open source escape hatch is what’s driving the adoption of Mattermost.
we power chat for over 1b users. you are very likely using our chat (strava, nextdoor, match, adobe, patreon, and many others)
closed source but you can export your data when you want to. mattermost is an open source slack. we are more of an API/SDK to build your own in-app chat/messaging as you want it.
You can integrate it into your app at far lower costs. Actually for what you're doing we're happy to sponsor the hosting at no costs.