Best Free Chat & Communication for self-hosting

Scalable real-time messaging server for apps and websites

Replaces Pusher, Firebase Realtime Database

Screen sharing for developers

Typebot

Chat & Communication

Conversational app builder (alternative to Typeform and Landbot)

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

Self-hostable WebSocket server compatible with Pusher

Replaces Pusher

Scalable software telephony platform

Replaces Twilio, Asterisk

Ferdium

Chat & Communication

All-in-one messenger that combines chat services

Replaces Rambox, Station

Asterisk

Chat & Communication

Open-source framework for building telephony systems

Replaces Avaya, Cisco Unified Communications

Extensible terminal-based chat client

Replaces Slack

Modular terminal IRC client with scripting

Replaces Slack

Open-source XMPP chat client for Android with OMEMO encryption

Replaces WhatsApp, Signal

High-performance SIP server for VoIP infrastructure

Replaces Twilio

Peer-to-peer encrypted messaging protocol and core

Replaces Skype, Discord

Stoat

Chat & Communication

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

AnyCable

Chat & Communication

Real-time WebSocket server for in-app messaging

Replaces Pusher, Ably

Chitchatter

Chat & Communication

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

Live Support chat for your website

Feature-rich event management system

Replaces Zoho Backstage

Secured and decentralized communication system

Troubleshooting and monitoring VoIP calls

Peer-calls

Chat & Communication

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

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

GlobaLeaks

Chat & Communication

Whistleblowing software enabling anyone to easily set up and maintain

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

Lightweight videoconferencing server

Replaces Zoom, Google Meet

Anonymously share files, browse and publish _freesites_ (web sites

Multi-tenant web GUI for FreeSWITCH

Replaces 3CX, RingCentral

Web front end for the WeeChat IRC relay

Replaces IRCCloud, Slack

Conference management software

Replaces Zoho Backstage

Multichannel notification server with support for Email, Mobile Push,

Messaging platform operating without user identifiers

OTS

Chat & Communication

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

Peer-to-peer encrypted messaging that works offline

Replaces Signal, WhatsApp

Distributed IRC client with an always-on core

Replaces Slack

Command-line tool for sending and receiving Matrix messages

Replaces Slack CLI

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-to-cam video calls and screen sharing

Open-source SIP voice, video, and messaging client

Replaces Skype, Zoom

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

Server for unified push support in Molly chat application

Self-hosted name registry and bridge for the Jami network

Replaces Skype, Zoom

Notification server for relaying push notifications via Matrix,

IRC services suite for nickname and channel registration

Replaces Slack

E2E-encrypted personal-server messaging app

Replaces Discord, Slack

Bouncer-style Matrix to IRC bridge

Replaces ZNC

XMPP library for building bots and chat extensions

Replaces Slack apps

Self-hosted backend for syncing Ferdium settings

Replaces Franz Server

IRCv3 server daemon used by Libera.Chat

Replaces Slack, Discord

P2P encrypted messaging protocol toolkit

Replaces Signal, WhatsApp

Moderation bot for Matrix communities

Replaces Discord moderation bots

Self-hosted AI assistant bot for Matrix rooms

Replaces Slack AI assistants

Standalone media storage for Matrix homeservers

Replaces Slack file storage

Truly private space for you and your friends

Federated commenting system built on Matrix

Replaces Disqus

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

Next-Gen self-hosted chat server and clients

Matrix bot that generates news summaries from chat

Replaces Slack workflows

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

Electronic mailing lists manager

Replaces Google Groups

Simple and efficient mailing list manager

Simple web frontend for Mlmmj mailing list management

Secure Scuttlebutt pub with a web interface for pub management

Replaces Facebook, Instagram

TrueConf

Chat & Communication

Platform for your corporate communications, based on the advanced

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

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

Freepbx

Chat & Communication

Web-based open source GUI that controls and manages Asterisk

Software framework for decentralized, peer-to-peer networking

VoIP troubleshooting and monitoring platform