Nextiva - Business VoIP, cloud phone systems trusted by more than 150,000 companies. Powered by the leading cloud PBX VoIP platform, Nextiva is rated the best business VoIP service provider.

Zoiper - Cross-platform VoIP softphone dialer for SIP and IAX systems

Dialpad - Switch is a cloud-based phone system built for Google Apps users.

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

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