Ringless voicemail, also called a voicemail drop or RVM, is a method in which a pre-recorded audio message is placed in a voicemail inbox without the associated telephone ringing first.
Can I use CallRail for ringless voicemail?
No, we do not provide the ability to deliver ringless voicemail messages.
According to a ruling published by U.S. District Judge Gordon J. Quist on July 16, 2018, ringless voicemail was determined to be a "call" that is subject to TCPA regulations.
This has the effect of making voicemail drops that contain an unsolicited advertisement illegal in many circumstances. Such messages are a violation subject to fines and civil liability.