FreeSWITCH
5.2kScalable open source cross-platform telephony platform.
Communication - SIPMPL-2.0
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.
Scalable open source cross-platform telephony platform.
Easy to use but advanced IP PBX system, VoIP gateway and conference server.
Modular SIP server (registrar/proxy/router/etc).
Troubleshooting and monitoring VoIP calls.
Lightweight SIP proxy, location server, and registrar for a reliable and scalable SIP infrastructure.
SIP proxy/server for voice, video, IM, presence and any other SIP extensions.