Open-source communication tools to replace Slack, Discord, and hosted chat — self-host on your infrastructure.
173 projects
Federated microblogging server.
Advanced forum / community solution based on Ruby and JS.
Communications platform that puts data protection first (alternative to Gitter.im and Slack).
Notification infrastructure for developers.
Platform for secure collaboration across the entire software development lifecycle, can be integrated with Gitlab (alternative to Slack).
Customer communication platform (alternative to Intercom and Zendesk).
Push notifications to phone or desktop using HTTP PUT/POST, with Android app, CLI and web app, similar to Pushover and Gotify.
WebRTC application that uses Jitsi Videobridge to provide high quality, scalable video conferences.
Zulip is a powerful, open source group chat application.
High performance, self-hosted newsletter and mailing list manager with a modern dashboard.
Production-ready fullstack but simple mail server (SMTP, IMAP, LDAP, Antispam, Antivirus, etc.) running inside a container. Only configuration files, no SQL database.
The most private and secure chat and applications platform - now with double ratchet E2E encryption.
Apprise allows you to send a notification to almost all of the most popular notification services available to us today such as: Telegram, Discord, Slack, Amazon SNS, Gotify, etc.
Complete and fully featured mail server for use by websites & web servers.
Delightfully simple forums. Flarum is the next-generation forum software that makes online discussion fun again.
Knowledge-based community software. You can use it to quickly build your Q&A community for product technical support, customer support, user communication, and more.
Turns any Ubuntu server into a fully functional mail server with one command.
Notification server with Android and CLI clients (alternative to PushBullet).
Forum software built for the modern web.
Link aggregator for the fediverse (alternative to Reddit).
Distributed social networking server.
All-in-one mail server with JMAP, IMAP4, and SMTP support and a wide range of modern features.
Instant messaging platform. Backend in Go. Clients: Swift iOS, Java Android, JS webapp, scriptable command line; chatbots.
Fully-featured Matrix client for Web, iOS & Android.
Mail server suite based on Dovecot, Postfix and other open source software, that provides a modern Web UI for administration.
Decentralized app-like microblogging server/SNS for the Fediverse, using the ActivityPub protocol like GNU social and Mastodon.
Language-agnostic real-time messaging (Websocket or SockJS) server.
Screego is a simple tool to quickly share your screen to one or multiple people via web browser.
Conversational app builder (alternative to Typeform and Landbot).
Marketing automation software (email, social and more).
Supports real-time sharing of audio, video, slides (with whiteboard controls), chat, and the screen. Instructors can engage remote students with polling, emojis, and breakout rooms.
General-purpose, lightweight, minimalist WebRTC Server.
Low-latency, high quality voice/text chat software.
Simple yet full-featured mail server as a set of Docker images.
Browser-based IMAP client with an application-like user interface.
Ethical photo sharing platform, powered by ActivityPub federation (alternative to Instagram).
Open source email alias solution to protect your email address. Comes with browser extensions and mobile apps.
XMPP instant messaging server.
Flexible kit for private social networks.
Self-hosted web IRC client.
All-in-one mail server that implements SMTP (both MTA and MX) and IMAP. Replaces Postfix, Dovecot, OpenDKIM, OpenSPF, OpenDMARC with single daemon.
Complete e-mail solution with IMAP4, SMTP, SPF, DKIM, DMARC, MTA-STS, DANE and DNSSEC, reputation-based and content-based junk filtering, Internationalization (IDNA), automatic TLS with ACME and Let's Encrypt, account autoconfiguration, and webmail.
Fast, highly extensible, and event driven SMTP server.
Virtual office / virtual conference application presented as a 16-bit RPG video game.
Lightweight and simple comment engine, which doesn't spy on users. It can be embedded into blogs, articles or any other place where readers add comments.
Lightweight commenting server written in Python and Javascript. It aims to be a drop-in replacement for Disqus.
Scalable open source cross-platform telephony platform.
Email forwarding service for creating aliases.
Simple, secure, fast real-time video conferences up to 4k and 60fps, compatible with all browsers and platforms.
Server for [Matrix](https://matrix.org/), an open standard for decentralized persistent communication.
Mail hosting and management platform including a modern and simplified web user interface.
An alternative private front-end to Reddit, with its origins in Libreddit.
Easy to use but advanced IP PBX system, VoIP gateway and conference server.
Fast, light and extensible chat client.
XMPP chat client in your browser.
Modern IRCv3 server written in Go, combining the features of an ircd, a services framework, and a bouncer.
WebRTC compatible Selective Forwarding Unit (SFU) that allows for multiuser video communication.
Real time collaboration (RTC) server.
Simple, secure, scalable real-time video conferences up to 4k, compatible with all browsers and platforms.
Share sensitive information securely with self-destructing links that are only viewable once.
Modular SIP server (registrar/proxy/router/etc).
Fully featured modern forum application that is fast, scalable and responsive.
Distributed, secure messenger with audio and video chat capabilities.
Web Whiteboard to collaborate in real-time on schemas, drawings, and notes.
Collaborative decision-making tool that makes it easy for anyone to participate in decisions which affect them.
Stoat is a user-first chat platform built with modern web technologies.
Realtime server for reliable two-way communication over WebSockets, Server-sent events, etc.
Peer-to-peer chat app that is serverless, decentralized, and ephemeral.
High-performance and feature-rich chat server for Matrix, and the successor to conduwuit (fork of Conduit).
Comment system built in Golang, providing a lightweight and highly customizable solution for adding comments to your website.
Live Support chat for your website.
Reliable and easy-to-use newsletter tool (alternative to Mailchimp and Sendinblue).
Advanced IRC bouncer.
Scalable no-SPOF IMAP/POP3 mail server.
Flat-forum bulletin board software solution that can be used to stay in touch with a group of people or can power your entire website.
Modern, federated social network based on XMPP, with a fully featured group-chat, subscriptions and microblogging.
Secured and decentralized communication system. Offers decentralized chat, forums, messaging, file transfer.
A better commenting experience from Vox Media.
Troubleshooting and monitoring VoIP calls.
Full-featured mail server solution based on Postfix and Dovecot.
Create a community, where your users can suggest ideas and get questions answered. And have friendly open-ended discussions and chat (Slack/StackOverflow/Discourse/Reddit/Disqus hybrid).
Mobile messaging platform with a focus on performance and scalability.
Lightweight SIP proxy, location server, and registrar for a reliable and scalable SIP infrastructure.
Social Communication Server.
Powerful open source social networking engine.
Simple, modern, lightweight & fast web-based email client (fork of RainLoop).
Feed reader for your email accounts.
Privacy-focused encrypted email for everyone. All-in-one alternative to Gmail + Mailchimp + Sendgrid.
Whistleblowing software enabling anyone to easily set up and maintain a secure reporting platform.
SIP proxy/server for voice, video, IM, presence and any other SIP extensions.
Federated, end-to-end encrypted messaging service for the web, iOS, and Android, supporting text, photos, video, and WebRTC video and audio calls.
Your Debian-based data center in a box. A set of general-purpose Ansible roles that can be used to manage Debian or Ubuntu hosts.
Video conferencing server that is easy to deploy and that requires moderate server resources.
Modular IRC server written in C++ for Linux, BSD, Windows, and macOS.
Free, extensible forum software package.
IMAP and POP3 server written primarily with security in mind.
Social networking software that allows you to make a social networking website and helps your members build social relationships, with people who share similar professional or personal interests.
Anonymously share files, browse and publish _freesites_ (web sites accessible only through Hyphanet) and chat on forums.
Web interface for multi-platform voice switch called FreeSWITCH.
Responsive web IRC client with theming support.
A web frontend for WeeChat.
A simple, fast, and reliable chat server powered by Matrix.
Stack Overflow in a JAR. An enterprise-ready Q&A platform with full-text search, SAML, LDAP integration and social login support.
Multichannel notification server with support for Email, Mobile Push, Web Push, SMS, messaging and a javascript plugin.
Complete trashmail solution that exposes an SMTP server and has a web interface to manage received emails. Works with multiple and wildcard domains and is fully file based (no database needed). Includes RSS feeds and JSON API.
Newsletter and email marketing with advanced management of subscribers, bounces, and plugins.
Distributed IRC client, meaning that one (or multiple) client(s) can attach to and detach from a central core.
One-Time-Secret sharing platform with a symmetric 256bit AES encryption in the browser.
POP/IMAP/SMTP/Caldav/Carddav/LDAP exchange gateway allowing users to use any mail/calendar client with an Exchange server, even from the internet or behind a firewall through Outlook Web Access.
Free, professional grade software package that allows you to set up your own online community within minutes.
Enigma 1/2 is a modern, multi-platform BBS engine with unlimited "callers" and legacy DOS door game support.
Email (IMAP/POP3), contacts and calendar server.
Privacy-friendly and customizable Disqus (comment system) alternate.
Secure SMTP server implementation from the OpenBSD project.
Portable and lightweight Internet Relay Chat server for small or private networks.
Modular, advanced and highly configurable IRC server written in C for Linux, BSD, Windows, and macOS.
Real-time cam-2-cam video calls & screen sharing, end-to-end encrypted, to embed in any website with a simple iframe.
Scalable and high performance web conferencing system.
Q&A-based community knowledge-sharing software.
All-in-one Dockerized easy XMPP solution, including web admin and clients.
Spectrum 2 is an open source instant messaging transport. It allows users to chat together even when they are using different IM networks.
Keep secrets out of emails or chat logs, share them using secure links with passphrase and expiration dates.
Federated and decentralized profile builder and social network engine.
Notification server for relaying push notifications via Matrix, similar to PushBullet and Gotify.
XMPP server implementation in Java.
Complete mailserver solution leveraging the Nix Ecosystem.
All-in-one customer engagement platform from lead-gen to post-sales, from WhatsApp to your website. With omni-channel live agents and AI-powered chatbots (alternative to Intercom, Zendesk, Tawk.to and Tidio).
Mailing list manager.
A small MTA for home and office use. Works on Linux and FreeBSD.
Bridge that interacts with Fediverse on behalf of your static site.
Powerful plugin that takes your WordPress.org powered site beyond the blog with social-network features like user profiles, activity streams, user groups, and more.
Access GNU Mailman v3 archives.
IRC without netsplits. Distributed IRC server, based on RobustSession protocol.
Complete, modular and scalable SIP server, includes a push gateway, to deliver SIP incoming calls or text messages on mobile device platforms where push notifications are required to receive information when the app is not active in the foreground.
Next-Gen self-hosted chat server and clients.
Web user interface to access GNU Mailman.
Full-featured PABX system, with call queues, built-in web conferencing, live chat and social media messaging all on one system.
Federated microblogging server with Mastodon, GNU social, and ActivityPub compatibility.
Fast, SQLite-powered forum engine written in ASM.
SMTP (email) server with a focus on simplicity, security, and ease of operation.
Community-driven Matrix homeserver, the continuation of conduwuit focusing on user experience and new features (fork of Conduit).
Fast, scalable, enterprise mail/groupware server providing ESMTP, IMAP, POP3, webmail, mailing list, basic web-based calendaring and scheduling services.
SMTP server that sends and receives emails according to a simple configuration file, with an optional web interface that you can use to browse your emails.
A small and easy to configure SMTP and POP3 server for Windows and Linux.
Message transfer agent (MTA) developed at the University of Cambridge.
Web-based open source GUI that controls and manages Asterisk.
Software framework for decentralized, peer-to-peer networking.
ActivityPub federated social network server implementing the Mastodon client API.
Online whiteboard, audio/video conferencing, screen sharing, shared code editing and optional session recording/playback.
Decentralized identity, privacy, publishing, sharing, cloud storage, and communications/social platform.
Federated microblogging server that communicates over ActivityPub.
Lets you have an infinite number of unique inboxes.
Universal communication platform which preserves the user's privacy and freedoms.
Web frontend from Salut à Toi.
Manage electronic mail discussion and e-newsletter lists.
Mailing list management made joyful.
A link aggregator / reddit clone for the fediverse (alternative to Reddit).
Federated microblogging server, Mastodon, GNU social, & ActivityPub compatible.
Fast, easy to administer, and secure Sendmail replacement.
Alternative private mail system - web-based, end-to-end encrypted by design, self-hosted, decentralized, uses independent PKI. Easy to install and administrate, freeware, open-source.
Feature-rich and easy to configure XMPP server.
VoIP troubleshooting and monitoring platform.
Multipurpose, multi frontend, libre and decentralized communication tool.
GPG-enabled mailing list manager with resending-capabilities.
Message transfer agent (MTA).
Self-hosted email newsletter application that lets you send bulk emails via Amazon Simple Email Service (SES) or other SMTP services.
Another browser-based IMAP client.
Platform for your corporate communications, based on the advanced architecture, with support for UltraHD video conferencing, built-in messenger with personal and group chats, and a free version for up to 1,000 users.
Instant messaging and collaboration tool with private and group chat rooms, continuous voice and video meetings, files sharing, issue tracking with integrated task board (alternative to Slack).
Full-featured IPBX solution built atop Asterisk with integrated Web administration interface and REST-ful API.
Transit class4 softswitch(SBC) with integrated billing and routing engine and REST API.
Complete email solution that runs on any webspace with PHP and MariaDB. It supports POP3 catchall mailboxes and can also integrate with Postfix or b1gMailServer if you're running your own server.
Self-Hosted, Twitter™-like Decentralised micro-logging platform. No ads, no tracking, your content, your data.
Curated from Awesome Self-Hosted and GitHub. Verify license and security before self-hosting in production.