- [Pushjet](https://pushjet.io/) - Self hosted push notification service built with a simple API making sending notifications easy. ([Source Code](https://github.com/Pushjet/Pushjet-Server-Api)) `BSD-2-Clause``Python`
- [Pushjet](https://pushjet.io/) - Self hosted push notification service built with a simple API making sending notifications easy. ([Source Code](https://github.com/Pushjet/Pushjet-Server-Api)) `BSD-2-Clause``Python`
- [Rallly](http://rallly.co) - Rallly is a free collaborative scheduling service. ([Source Code](https://github.com/lukevella/Rallly)) `CC-BY-SA-4.0``Nodejs`
- [Rallly](http://rallly.co) - Rallly is a free collaborative scheduling service. ([Source Code](https://github.com/lukevella/Rallly)) `CC-BY-SA-4.0``Nodejs`
- [RetroShare](http://retroshare.org) - Secured and decentralized communication system. Offers decentralized chat, forums, messaging, file transfer. ([Source Code](https://github.com/RetroShare/RetroShare)) `GPL-2.0``С++`
- [RetroShare](http://retroshare.org) - Secured and decentralized communication system. Offers decentralized chat, forums, messaging, file transfer. ([Source Code](https://github.com/RetroShare/RetroShare)) `GPL-2.0``С++`
- [Ring](https://ring.cx/) - Free software for universal communication which respects freedoms and privacy of its users. ([Source Code](https://github.com/savoirfairelinux/ring-project)) `GPL-3.0``C++`
- [Jami](https://jami.net/) - Free and universal communication platform which preserves the user's privacy and freedoms (formerly GNU Ring). ([Source Code](https://git.ring.cx/savoirfairelinux/ring-project)) `GPL-3.0``C++`
- [Rocket.Chat](https://rocket.chat/) - Teamchat solution similar to Gitter.im or Slack. ([Source Code](https://github.com/RocketChat/Rocket.Chat)) `MIT``Nodejs`
- [Rocket.Chat](https://rocket.chat/) - Teamchat solution similar to Gitter.im or Slack. ([Source Code](https://github.com/RocketChat/Rocket.Chat)) `MIT``Nodejs`
- [Spectrum 2](http://spectrum.im/) - Spectrum 2 is an open source instant messaging transport. It allows users to chat together even when they are using different IM networks. ([Source Code](https://github.com/hanzz/spectrum2)) `GPL-3.0``C++`
- [Spectrum 2](http://spectrum.im/) - Spectrum 2 is an open source instant messaging transport. It allows users to chat together even when they are using different IM networks. ([Source Code](https://github.com/hanzz/spectrum2)) `GPL-3.0``C++`
- [Spreed](https://www.spreed.me/) - WebRTC audio/video calls, conferencing server, and web client. ([Source Code](https://github.com/strukturag/spreed-webrtc)) `AGPL-3.0``Go`
- [Spreed](https://www.spreed.me/) - WebRTC audio/video calls, conferencing server, and web client. ([Source Code](https://github.com/strukturag/spreed-webrtc)) `AGPL-3.0``Go`