Chat vs Microsoft Teams
Chat and Microsoft Teams are both team chat software. Chat is open source under GPL-3.0, with 14k GitHub stars. Microsoft Teams is a commercial product from Microsoft.
Which to pick
- Pick Chat when
- You want to embed or run your own messaging service with ready clients.
- Pick Microsoft Teams when
- Your business already pays for Microsoft 365 and wants chat and video meetings without another vendor.
Side by side
An instant messaging server in Go with web, Android and iOS clients, group chats and a chatbot API.
Chat, meetings, calls and file collaboration built on Microsoft 365, with SharePoint behind team files and optional phone system.
Still pre-1.0 after many years, with a small team.
The client is heavy and the chat experience is clumsier than Slack; in the EU it is now sold separately from some Microsoft 365 plans.
Usable
Production-ready
Self-hosted server and mobile app
Cloud service, desktop app and mobile app
Go, PostgreSQL, MySQL and MongoDB
Not published
Open source, GPL-3.0 (strong copyleft)
Closed source, sold by Microsoft
Use inside your business is unrestricted, but anything you distribute that includes it must be released under the same license.
Closed source: you use it under the maker's terms and cannot change or resell the code.
14k GitHub stars
20k Wikipedia readers a month on phones
Established: started 12 years ago, latest release v0.25.3.
Not known
Other comparisons
More team chat apps
Both sides were judged on 2026-11-03 from makers' descriptions, Wikipedia, READMEs and GitHub data. License, age and popularity lines are worked out directly.