Best Multi-User Chat & Communication for self-hosting

Open-source customer engagement and live-chat platform

Replaces Intercom, Zendesk

Real-time collaborative document editor

Replaces Google Docs

Screen sharing for developers

Conversational app builder (alternative to Typeform and Landbot)

Modern, self-hosted web IRC client

Replaces IRCCloud, Slack

Open-source live chat and customer messaging

Replaces Intercom, Drift

Web-based helpdesk and customer support system

Replaces Zendesk, Freshdesk

Virtual office / virtual conference application presented as a 16-bit

Privacy-focused lightweight commenting engine

Replaces Disqus

Lightweight self-hosted commenting server

Replaces Disqus

Scalable software telephony platform

Replaces Twilio, Asterisk

Free self-hosted help desk and shared inbox

Replaces Help Scout, Zendesk

Open-source framework for building telephony systems

Replaces Avaya, Cisco Unified Communications

Modern IRC server with IRCv3 and bouncer features

Replaces Slack, Discord

XMPP gateway providing phone-number based messaging

Replaces WhatsApp, Signal

High-performance SIP server for VoIP infrastructure

Replaces Twilio

Lightweight, privacy-friendly embeddable comment system

Replaces Disqus

Stoat is a user-first chat platform built with modern web technologies

Peer-to-peer chat app that is serverless, decentralized, and ephemeral

Live Support chat for your website

Self-hostable, open-source Discord-compatible chat backend

Replaces Discord

Chat, video calls and webinars integrated into Nextcloud

Replaces Slack, Zoom

Feature-rich event management system

Replaces Zoho Backstage

Secured and decentralized communication system

Troubleshooting and monitoring VoIP calls

Group peer to peer video calls for everyone

Replaces BigBlueButton, Skype

Matrix-Telegram puppeting bridge

Replaces Telegram official client

Lightweight SIP proxy, location server, and registrar for a reliable

Whistleblowing software enabling anyone to easily set up and maintain

SIP proxy/server for voice, video, IM, presence and any other SIP

Federated, end-to-end encrypted messaging service for the web, iOS,

Modular C++ Internet Relay Chat daemon

Replaces Slack, Discord

JavaScript-based multi-user XMPP chat client

Replaces Chatango

Terminal-based client for the Tox messaging network

Replaces Skype, WhatsApp

Anonymously share files, browse and publish _freesites_ (web sites

Multi-tenant web GUI for FreeSWITCH

Replaces 3CX, RingCentral

User-friendly IRC bouncer with multi-network support

Replaces IRCCloud

Federated social networking toolkit for communities

Replaces Facebook Groups, Discord

Conference management software

Replaces Zoho Backstage

Multichannel notification server with support for Email, Mobile Push,

Distributed IRC client with an always-on core

Replaces Slack

One-Time-Secret sharing platform with a symmetric 256bit AES

Privacy-friendly, self-hosted web comments engine

Replaces Disqus

IRC gateway to instant messaging networks

Replaces Pidgin

Lightweight Unix IRC server that is easy to configure

Replaces Slack

Self-hosted multi-room chat with markdown and code blocks

Replaces Discord, Slack

Scalable signaling backend for Nextcloud Talk

Replaces Zoom

Highly configurable open-source IRC server

Replaces Slack, Discord

Real-time cam-2-cam video calls & screen sharing, end-to-end

Bridge connecting Matrix rooms to IRC channels

Replaces Slack IRC gateway

Minimal email server tuned for Delta Chat messaging

Replaces WhatsApp, Signal

Modular IRC services framework for large networks

Replaces Slack

Transport and gateway framework for messaging networks

Replaces Bitlbee

Keep secrets out of emails or chat logs, share them using secure links

Self-hosted name registry and bridge for the Jami network

Replaces Skype, Zoom

Server for unified push support in Molly chat application

Notification server for relaying push notifications via Matrix,

IRC services suite for nickname and channel registration

Replaces Slack

Self-hosted backend for syncing Ferdium settings

Replaces Franz Server

IRCv3 server daemon used by Libera.Chat

Replaces Slack, Discord

Moderation bot for Matrix communities

Replaces Discord moderation bots

Standalone media storage for Matrix homeservers

Replaces Slack file storage

IRC server daemon for large networks

Replaces Discord, Slack

Truly private space for you and your friends

Lightweight and stable IRC server daemon

Replaces Slack, Discord

Secure Scuttlebutt room server

IRC without netsplits

Complete, modular and scalable SIP server, includes a push gateway, to

Next-Gen self-hosted chat server and clients

XMPP to IRC gateway component

IRC server daemon used by the Undernet network

Replaces Discord, Slack

Multi-frontend XMPP communication ecosystem

Replaces Slack, Facebook

Continuously relays a remote IMAP inbox into a YunoHost mailbox

Bot which enables multiple Matrix users to use a single third-party IM

Simple plaintext email send app

Simple and efficient mailing list manager

Secure Scuttlebutt pub with a web interface for pub management

Replaces Facebook, Instagram

Platform for your corporate communications, based on the advanced

Alternative private mail system - web-based, end-to-end encrypted by

Full-featured PABX system, with call queues, built-in web

Online whiteboard, audio/video conferencing, screen sharing, shared

Full-featured IPBX solution built atop Asterisk with integrated Web

Transit class4 softswitch(SBC) with integrated billing and routing

Web-based open source GUI that controls and manages Asterisk

Software framework for decentralized, peer-to-peer networking

VoIP troubleshooting and monitoring platform