- [Kamailio](http://www.kamailio.org/w/) - Modular SIP server (registrar/proxy/router/etc). ([Source Code](https://github.com/kamailio/kamailio)) `GPL-2.0``C`
- [Kamailio](http://www.kamailio.org/w/) - Modular SIP server (registrar/proxy/router/etc). ([Source Code](https://github.com/kamailio/kamailio)) `GPL-2.0``C`
- [Kazoo](http://2600hz.org/) - KAZOO is an open-source, highly scalable software platform designed to provide carrier-grade VoIP switch functions and features. ([Source Code](https://github.com/2600hz/KAZOO)) `MPL-1.1``Erlang`
- [Kazoo](http://2600hz.org/) - KAZOO is an open-source, highly scalable software platform designed to provide carrier-grade VoIP switch functions and features. ([Source Code](https://github.com/2600hz/KAZOO)) `MPL-1.1``Erlang`
- [Routr](https://routr.io) - A lightweight sip proxy, location server, and registrar for a reliable and scalable SIP infrastructure. ([Demo](https://demo.routr.io/login), [Source Code](https://github.com/fonoster/routr)) `MIT``JavaScript`
- [Routr](https://routr.io) - A lightweight sip proxy, location server, and registrar for a reliable and scalable SIP infrastructure. ([Source Code](https://github.com/fonoster/routr)) `MIT``JavaScript`
- [SIP3](https://sip3.io/) - VoIP troubleshooting and monitoring platform. ([Demo](https://demo.sip3.io), [Source Code](https://github.com/sip3io/)) `Apache-2.0``Kotlin`
- [SIP3](https://sip3.io/) - VoIP troubleshooting and monitoring platform. ([Demo](https://demo.sip3.io), [Source Code](https://github.com/sip3io/)) `Apache-2.0``Kotlin`
- [Wazo](http://wazo-platform.org/) - Full-featured IPBX solution built atop Asterisk with integrated Web administration interface and REST-ful API. ([Source Code](https://github.com/wazo-platform)) `GPL-3.0``Python`
- [Wazo](http://wazo-platform.org/) - Full-featured IPBX solution built atop Asterisk with integrated Web administration interface and REST-ful API. ([Source Code](https://github.com/wazo-platform)) `GPL-3.0``Python`