Radicale
Simple server for calendars (CalDAV) and contacts (CardDAV).
GPL-3.0Strong copyleft
SaaS: YesClosed product: No
Open source in Communication
Team chat, video meetings, email and calendar.
Common tools in this category
Open-source products · 43
Calendar & contacts server
Email server & webmail
docker-mailserver
Complete mail server in a container with SMTP, IMAP, spam filtering and antivirus.
MITPermissive
SaaS: YesClosed product: Yes
Postal
Platform for sending and receiving email at scale, with an API and delivery tracking.
MITPermissive
SaaS: YesClosed product: Yes
Mail-in-a-Box
Makes it easy to set up your own mail server with everything needed on a dedicated machine.
CC0-1.0Permissive
SaaS: YesClosed product: Yes
Stalwart Mail Server
Mail and collaboration server in Rust supporting IMAP, JMAP, SMTP, calendars and contacts.
AGPL-3.0Network copyleft (AGPL)
SaaS: Yes, with conditionsClosed product: No
mailcow
Mail server in Docker with webmail, groupware, spam filtering and an admin interface.
GPL-3.0Strong copyleft
SaaS: YesClosed product: No
Mailu
Email server that runs as Docker containers, with webmail and spam filtering.
MITPermissive
SaaS: YesClosed product: Yes
Roundcube
Webmail client that connects to existing IMAP servers.
GPL-3.0Strong copyleft
SaaS: YesClosed product: No
Maddy Mail Server
Mail server in a single program that replaces several separate parts (SMTP, IMAP, DKIM and similar).
GPL-3.0Strong copyleft
SaaS: YesClosed product: No
Mox
Modern mail server in a single program, built to be easy to run yourself.
MITPermissive
SaaS: YesClosed product: Yes
Modoboa
Mail hosting platform with a web admin for domains, accounts and filters.
ISCPermissive
SaaS: YesClosed product: Yes
WildDuck
Scalable IMAP and POP3 server that stores mail in MongoDB.
EUPL-1.2Strong copyleft
SaaS: YesClosed product: No
iRedMail
Script that installs a complete mail server on mainstream Linux and BSD systems.
GPL-3.0Strong copyleft
SaaS: YesClosed product: No
SnappyMail
Fast, simple webmail client for IMAP accounts.
SaaS: Yes, with conditionsClosed product: No
Live streaming
SRS
Media server for live streaming supporting RTMP, WebRTC, HLS, SRT and more protocols.
MITPermissive
SaaS: YesClosed product: Yes
PeerTube
Video platform for publishing and streaming video, federated with other servers via ActivityPub.
AGPL-3.0Network copyleft (AGPL)
SaaS: Yes, with conditionsClosed product: No
Owncast
Self-hosted live streaming with built-in chat, an alternative to streaming through Twitch or YouTube.
MITPermissive
SaaS: YesClosed product: Yes
Restreamer
Self-hosted streaming server with a web interface that can forward streams to several platforms.
Apache-2.0Permissive
SaaS: YesClosed product: Yes
MediaCMS
Video platform and media library with uploads, categories, permissions and a REST API.
AGPL-3.0Network copyleft (AGPL)
SaaS: Yes, with conditionsClosed product: No
OvenMediaEngine
Live streaming server with sub-second latency via WebRTC and LL-HLS.
AGPL-3.0Network copyleft (AGPL)
SaaS: Yes, with conditionsClosed product: No
Team chat
Mattermost
Slack-style team chat with channels, threads and integrations.
SaaS: Yes, with conditionsClosed product: No
Rocket.Chat
Team and customer chat with federation.
SaaS: YesClosed product: Yes
Zulip
Team chat organised into topic threads.
Apache-2.0Permissive
SaaS: YesClosed product: Yes
Element / Synapse (Matrix)
Federated, encrypted chat on the Matrix protocol; used by European public sector.
AGPL-3.0Network copyleft (AGPL)
SaaS: Yes, with conditionsClosed product: No
Element
Matrix chat client with messaging, calls and end-to-end encryption on the web, desktop and mobile.
AGPL-3.0Network copyleft (AGPL)
SaaS: Yes, with conditionsClosed product: No
Campfire
Simple group chat from 37signals that you install and run yourselves, without a subscription.
MITPermissive
SaaS: YesClosed product: Yes
tuwunel (Matrix server)
Lightweight Matrix server in Rust, successor to conduwuit.
Apache-2.0Permissive
SaaS: YesClosed product: Yes
Telephony / VoIP
FreeSWITCH
Software telephony platform for phone systems, conferencing and VoIP services.
MPL-1.1Weak copyleft
SaaS: YesClosed product: Yes, with conditions
Asterisk
Phone system and VoIP platform for calls, queues, voicemail and SIP trunks.
GPL-2.0Strong copyleft
SaaS: YesClosed product: No
Kamailio
SIP server for large VoIP and real-time communication platforms.
GPL-2.0Strong copyleft
SaaS: YesClosed product: No
OpenSIPS
SIP server for VoIP providers with routing, load balancing and billing.
GPL-2.0Strong copyleft
SaaS: YesClosed product: No
Video meetings & webinars
Jitsi Meet
Browser-based video meetings without an account.
SaaS: YesClosed product: Yes
LiveKit
Real-time audio and video platform over WebRTC, for apps and AI agents.
Apache-2.0Permissive
SaaS: YesClosed product: Yes
BigBlueButton
Web conferencing system for teaching and meetings with whiteboard, sharing and recording.
LGPL-3.0Weak copyleft
SaaS: YesClosed product: Yes, with conditions
Janus WebRTC Server
General-purpose WebRTC server used as a building block for video calls, conferencing and streaming.
GPL-3.0Strong copyleft
SaaS: YesClosed product: No
MiroTalk P2P
Self-hosted video meetings in the browser where participants connect directly to each other (P2P).
AGPL-3.0Network copyleft (AGPL)
SaaS: Yes, with conditionsClosed product: No
MiroTalk SFU
Self-hosted video meetings in the browser for larger groups, with screen sharing, chat and recording.
AGPL-3.0Network copyleft (AGPL)
SaaS: Yes, with conditionsClosed product: No
Meet (La Suite numérique)
Video meeting app from the French government's La Suite numérique, built on LiveKit.
MITPermissive
SaaS: YesClosed product: Yes
Nextcloud Talk
Chat, audio and video calls built into Nextcloud.
AGPL-3.0Network copyleft (AGPL)
SaaS: Yes, with conditionsClosed product: No
OpenVidu
Self-hosted platform for real-time audio and video in your own apps, built on LiveKit and mediasoup.
Apache-2.0Permissive
SaaS: YesClosed product: Yes
Galène
Lightweight video conferencing server that is easy to install and run.
MITPermissive
SaaS: YesClosed product: Yes