Twilio - Brings voice and messaging to your web and mobile applications.

Textnow.com - It lets you text your friends, aka my only source of happiness

Plivo - Plivo simplifies your customer engagement.

Dingtone - Dingtone is a free call and texting application for making unlimited calls and text messages to any number at the moment registered in any part of the world by any cellular company.

Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates

TextNow - TextNow is a mobile virtual network operator (MVNO) that provides a free phone service to users by using other cellular networks coverage.