Communication & Collaboration
43 self-hosted open source alternatives in this category
Calendars & Contacts (CalDAV/CardDAV)(28)Collaborative Office Suites(10)Email Servers (SMTP/IMAP)(36)Team Chat & Messaging(48)Video Conferencing & WebRTC(14)VoIP / SIP & PBX(11)Webmail Clients(14)
43 services found
Synapse
Matrix homeserver for decentralized, federated messaging
3.3k
435
Last commit: 2d ago
A Matrix homeserver that powers federated real-time chat with accounts, rooms, APIs, and integrations for clients like Element.
Alternative to:
Slack+4
Converse
Embeddable XMPP web chat client for websites and platforms
3.2k
801
Last commit: 4d ago
Converse is an open-source, browser-based XMPP/Jabber chat client you can embed in any site to provide 1:1 and group messaging over existing XMPP servers.
Alternative to:Slack+6
Baïkal
Lightweight CalDAV and CardDAV server for calendars and contacts
3k
304
Last commit: 4d ago
Baïkal is a lightweight CalDAV/CardDAV server for syncing calendars, tasks, and contacts with DAV clients, with a simple web admin UI and multi-user support.
Alternative to:
Google Calendar appointment scheduling+4
Ergo
Modern IRCv3 server with integrated services
3k
220
Last commit: 9d ago
Ergo is a modern, self-contained IRCv3 server with integrated services (NickServ/ChanServ), TLS, history playback, bouncers, and extensive IRCv3 capability support.
Alternative to:
Discord+5
YunoHost
A server OS to self-host apps easily on your own domain
2.8k
329
Last commit: 1d ago
Debian-based server distribution with a web admin, app catalog, SSO and automated TLS/DNS/email setup for easy, maintainable self-hosting.
Alternative to:
cPanel+5
AnyCable
Polyglot, high-performance WebSocket server for Action Cable
2.2k
110
Last commit: 4d ago
AnyCable is a scalable WebSocket server for Ruby on Rails Action Cable, offering a Go server with RPC to Rails and support for Redis and other brokers.
Alternative to:
Pusher Channels+4
Chitchatter
Peer-to-peer, serverless, ephemeral chat with E2EE
2.1k
344
Last commit: 10d ago
Chitchatter is a serverless, peer-to-peer chat app that uses WebRTC and end-to-end encryption for ephemeral rooms without storing messages on a central server.
Alternative to:Discord+4
sabre/dav
PHP WebDAV, CalDAV, and CardDAV server library
1.7k
362
Last commit: 5d ago
A PHP library for building WebDAV, CalDAV, and CardDAV servers with RFC-compliant protocol support, extensible plugins, and integration with existing authentication and storage backends.
Alternative to:Google Calendar appointment scheduling+5
SnappyMail
Modern, lightweight webmail client for IMAP and SMTP
1.5k
174
Last commit: 6mo ago
Fast, privacy-friendly webmail client with IMAP/SMTP, Sieve filters, PGP support, and a responsive UI. A community-driven continuation of RainLoop.
Alternative to:
Gmail+4
Cypht
A lightweight webmail client for IMAP accounts
1.4k
200
Last commit: 18d ago
Cypht is a lightweight, extensible webmail client that aggregates IMAP mailboxes and provides a fast, minimal UI with optional modules such as SMTP sending and Sieve filtering.
Alternative to:Gmail+2
Databag
Self-hosted end-to-end encrypted chat for groups and direct messages
1.4k
91
Last commit: 9d ago
Databag is a self-hosted, end-to-end encrypted messenger with group chat, file sharing, and multi-device access via web and native clients.
Alternative to:Slack+5
Dovecot
High-performance IMAP and POP3 server for Linux/Unix
1.2k
322
Last commit: 2d ago
Dovecot is an IMAP/POP3 mail server focused on performance, security, and standards compliance, commonly used for mailbox access in Postfix/Exim-based email stacks.
Alternative to:
Microsoft Exchange Online+4
Convos
A web-based IRC client with multi-user support
1.1k
92
Last commit: 11mo ago
Self-hosted web IRC client for individuals or teams with multi-user accounts, bouncer-like always-on connections, and a modern browser UI.
Alternative to:
IRCCloud+3