Some top alternatives to Ring4 includes RingByName, VoIPstudio, Vonage Business, PBX Plus by 500apps and MyOperator.
No, Ring4 doesn't provide API.
Yes, Ring4 provides a mobile app.
Ring4 is located in San Francisco, CA
Ring4 offers Freemium, Subscription pricing models
The starting price of Ring4 is $9.99/Month