Linphone - Linphone is an internet phone or Voice Over IP phone (VoIP).
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
Zoiper - Cross-platform VoIP softphone dialer for SIP and IAX systems
Crisp Chat - Multi-channel customer support software
Sipdroid - Free and open-source SIP/VoIP Client
Chaport Live Chat - Chaport is a beautiful, simple live chat for websites designed as a modern messenger.✨