Twilio - Brings voice and messaging to your web and mobile applications.
VideoScribe - Make your own whiteboard video animations with Sparkol VideoScribe – award-winning video scribing app for PC, Mac and iPad. Free trial available.
Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
Doodly - Create your own doodle video in just 60 seconds
Clockwork SMS - Clockwork is an Easy Text Message API. An SMS API for Developers. Build powerful apps and include SMS. Signup is free, Try it now.
TTS Sketch Maker - Create amazing whiteboard sketch videos with text-to-speech human-sounding voices in minutes!