Acrobits Softphone and Groundwire are both retail apps (for end users) and can be used with any VoIP provider. Acrobits Softphone is an app with a basic feature set while Groundwire caters more to business-oriented users with its attended and unattended transfers, 3-way conferencing, and more. Both apps support our signature feature – incoming calls via PUSH.
This feature allows users to receive calls even when the app is closed, significantly reducing battery drain in the process
If you are looking for an enterprise solution, check out Cloud Softphone.