Jenkins - Jenkins is an open-source continuous integration server with 300+ plugins to support all kinds of software development
Tragofone - White-label VoIP Softphone with WebRTC and Auto-provisioning
CircleCI - CircleCI gives web developers powerful Continuous Integration and Deployment with easy setup and maintenance.
PhonerLite - PhonerLite enables your PC to use it for internet telephony (VoIP , Voice over IP, SIP).
Travis CI - Focus on writing code. Let Travis CI take care of running your tests and deploying your apps.
tSIP - tomeko.net/software: SIP client for Windows.