Twilio

San Francisco-based Twilio already provides the cloud-communications backbone for some 36,000 customers, including Coca-Cola and Nordstrom. Its technology lets you message with your Uber driver, reminds you about appointments, and helps you generate passwords. Now it's expanding its capabilities--and mediums, especially into video. For example, telemedicine provider Doctor on Demand uses Twilio to connect doctors and patients via videoconferencing. "Voice and messaging are the biggest parts of our business, but video is coming on incredibly strong," says Patrick Malatack, Twilio's VP of product. --Kate Rockwood