Open-source alternatives to Slack

Secure communications platform for team collaboration — The Secure CommsOS™ for mission-critical operations

↔ alternative to Slack、Microsoft Teams

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、Microsoft Teams

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

Instant messaging and VoIP chat for groups — A free and open source instant messaging and VoIP chat app built for friends, groups, and communities.

↔ alternative to Discord、Slack

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

↔ alternative to Slack

Self-hosted instant messaging server — 即时通讯(IM)系统

↔ 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

Slack client that runs in your terminal — Slack client for your terminal

↔ alternative to Slack

Lightweight web client for Mastodon. — A nimble Mastodon web client

↔ alternative to Slack、Zoom

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

Aggregates messaging from many services — Franz is a free messaging app for services like WhatsApp, Slack, Messenger and many more.

↔ alternative to WhatsApp、Slack、Telegram

Simple group chat app — Super simple group chat, without a subscription

↔ alternative to Slack

Extensible chat client — The extensible chat client.

↔ alternative to Slack

Web-based XMPP/Jabber chat client — Web-based XMPP/Jabber chat written in JavaScript

↔ alternative to Slack

Searchable Slack/Discord community archive site — Lightweight Google-searchable Slack alternative for Communities

↔ 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

Minimal distraction-free chat application — a minimal, distraction-free chat application

↔ alternative to Slack

Federated social and chat platform powered by XMPP — Movim - Decentralized social platform

↔ 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

Matrix chat client written in Go — A Matrix client written in Go.

↔ alternative to Slack、Microsoft Teams、Discord

Desktop client for Rocket.Chat messaging — The Secure CommsOS™ for mission-critical operations

↔ alternative to Slack、Microsoft Teams

Instant messaging chat application — RelatedChat

↔ alternative to Slack、Microsoft Teams

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

↔ alternative to Slack、Microsoft Teams

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

↔ alternative to Slack

Desktop Matrix client for chat and collaboration — A glossy Matrix collaboration client for desktop.

↔ 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

Linux desktop client app for Slack — ScudCloud - Slack for Linux

↔ alternative to Slack

Wire for web — 👽 Wire for web

↔ alternative to Slack

Cross-platform chat and communication desktop app — :computer: Wire for desktop

↔ alternative to Slack、Microsoft Teams

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

Modern open source chat — A Cloudfuji chat application

↔ alternative to Slack