Best Open-source Team Chat Platforms tools

NodeBB

Real-time forum platform built on Node.js and websockets

Mattermost

Secure, extensible team collaboration platform for modern workflows

Discourse

Open-source community platform with discussions, chat, and plugins

Zulip

Threaded team chat that blends email clarity with real‑time speed

Rocket.Chat

Secure, customizable communication platform for teams and customers

Element

Matrix web client for secure, decentralized team communication

Misago

Modern, feature‑rich forum platform built with Django and React

Cinny

Simple, elegant Matrix client for modern instant messaging

Apache Answer

Open-source Q&A platform for teams of any scale

gomuks

Lightweight Matrix client built with Go and mautrix

Bitchat

Decentralized peer-to-peer chat using Bluetooth mesh and Nostr

Koishi

Cross-Platform Chatbot Framework with Rich Plugin Ecosystem

ejabberd

Scalable real-time messaging platform with XMPP, MQTT, and SIP

Flarum

Delightfully simple discussion platform for modern communities

Spacebar

Self‑hosted, Discord‑compatible chat, voice, and video platform.