XO Hosted PBX - Hosted PBX is a scalable UC solution that uses cloud technology to integrate HD voice & data services, mobility, along with advanced calling
Broadvoice - Cloud PBX solution for SMBs
Zoiper - Cross-platform VoIP softphone dialer for SIP and IAX systems
Genesys Cloud - As the foundation of great customer experience, the Genesys PureCloud contact center platform empowers your business to provide excellent service across the entire customer journey.
Sipdroid - Free and open-source SIP/VoIP Client
CallFire - Grow your business with virtual phone numbers, IVR, voice broadcasting, mass text messaging services and power dialing.