Slack - A messaging app for teams who see through the Earth!
Twilio - Brings voice and messaging to your web and mobile applications.
MS SharePoint - Share, organize, and discover information with Microsoft SharePoint. Learn about SharePoint Online, OneDrive for Business, and Apps for SharePoint
Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
Jostle - A new kind of employee intranet that drives engagement & workplace culture. Achieves social participation in work relevant way. Participation rates are over 85%.
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.