Open-source alternatives to Slack

Team chat and collaboration platform — The Secure CommsOS™ for mission-critical operations

↔ alternative to Slack

Self-hosted team chat and collaboration platform. — Mattermost is an open source platform for secure collaboration across the entire software development lifecycle..

↔ alternative to Slack

Organized team chat with topic-based threading — Zulip server and web application. Open-source team chat that helps teams stay productive and focused.

↔ alternative to Slack、Microsoft Teams

Self-hosted chat app for small teams — Self-hosted chat app for small teams

↔ alternative to Slack

macOS GUI for V2Ray — GUI for v2ray-core on macOS

↔ alternative to Slack、Zoom

Bridge messages across many chat platforms — bridge between mattermost, IRC, gitter, xmpp, slack, discord, telegram, rocketchat, twitch, ssh-chat, zulip, whatsapp, keybase, matrix, microsoft teams, nextcloud, mumble, vk and more with REST API (mattermost not required!)

↔ alternative to Slack

Distributed task scheduler and runner with web UI — A simple, distributed task scheduler and runner with a web based UI.

↔ alternative to Slack

Local-first Slack and Notion alternative — Open-source and local-first Slack and Notion alternative that puts you in control of your data

↔ alternative to Notion、Slack

Unified team workspace with email, chat and agents. — Macro is a unified workspace for teams: email, chat, docs, tasks, agents, calls, and CRM — @-linked together with shared AI memory.

↔ alternative to Notion、Slack

Simple self-hosted group chat without subscriptions. — Super simple group chat, without a subscription

↔ alternative to Slack

A Matrix collaboration client for Android. — A Matrix collaboration client for Android.

↔ alternative to Slack

Turn local filesystem into S3 object storage — A simple to deploy but feature rich S3 object storage server for your filesystem

↔ alternative to Jira、Slack、Zapier

Self-hosted team and group chat application. — A fully-featured team and group chat application that you can easily selfhost.

↔ alternative to Slack

Syncs Slack and Discord to a searchable site. — Lightweight Google-searchable Slack alternative for Communities

↔ alternative to Slack

Self-hosted team chat application — Kandan is an Open Source Alternative to HipChat

↔ alternative to Slack

Private P2P team chat over Tor and IPFS — A private, p2p alternative to Slack and Discord built on Tor & IPFS

↔ alternative to Slack、Discord

A terminal client for Slack — The best CLI client for Slack, because everything is terrible!

↔ alternative to Slack

The Mattermost desktop app for Windows, Mac and Linux. — Mattermost Desktop application for Windows, Mac and Linux

↔ alternative to Slack

Chat and video conferencing app for Nextcloud. — 🗨️ Nextcloud Talk – chat, video & audio calls for Nextcloud

↔ alternative to Zoom、Slack

Open source group messaging app for mobile. — Timy - open source mobile app for groups to communicate and organize themselves. Built with flutter.

↔ alternative to Slack

Desktop client for the Rocket.Chat team messenger. — The Secure CommsOS™ for mission-critical operations

↔ alternative to Slack

Open source Slack desktop client — Fast open source Slack desktop app

↔ alternative to Slack

Fast lightweight self-hosted messenger — fast & lightweight self-hosted messenger

↔ alternative to Slack

Collaborative real-time web chat application — Collaborative chat done right

↔ alternative to Slack、Microsoft Teams

Legacy Zulip team chat app for Android and iOS — Legacy Zulip mobile apps for Android and iOS

↔ alternative to Slack

Self-hosted team chat on Cloudflare with Telegram bridge. — 完全运行于 Cloudflare Worker的现代聊天系统：实时通信、Telegram 双向桥接、消息与文件加密 A modern, self-hosted team chat built on Cloudflare — realtime messaging, Telegram bridge, encrypted messages & files, and WebMCP. |

↔ alternative to Slack

Unofficial Linux desktop client for Slack. — ScudCloud - Slack for Linux

↔ alternative to Slack

End-to-end encrypted messaging for desktop. — :computer: Wire for desktop

↔ alternative to Slack、Microsoft Teams

Real-time chat app with MERN stack. — Real Time Chat App | MERN && Socket.io && JWT

↔ alternative to Slack

Web chat with DMs, groups, media and WebRTC calls — go-chat.使用Go基于WebSocket开发的web聊天应用。单聊，群聊。文字，图片，语音，视频消息，屏幕共享，剪切板图片，基于WebRTC的P2P语音通话，视频聊天。

↔ alternative to Slack、Discord、Microsoft Teams

Privacy centric Matrix chat client — ⚗️ a privacy centric matrix client

↔ alternative to Slack

Legacy native Rocket.Chat client for iOS. — Legacy mobile Rocket.Chat client in Swift for iOS

↔ alternative to Slack

Team communication tool optimized for deep work. — Team communication optimized for deep work

↔ alternative to Slack

Modern open source chat — A Cloudfuji chat application

↔ alternative to Slack

Secure open-source team collaboration platform — Twake is a secure open source collaboration platform to improve organizational productivity.

↔ alternative to Slack、Microsoft Teams