Appboy

When Bill Magnuson snagged an internship working for Google's Android division in 2009, the tech giant's smartphone was only six months old. But as mobile usage continued to grow, Magnuson realized that apps would eventually need to use a more sustainable monetization model to survive. Two years later, along with co-founders Jon Hyman and Mark Ghermezian, he built a mobile marketing platform called Appboy. The software helps companies learn more about phone users who download their app. Appboy collects the data by building out consumer profiles, which brands then use to send push notifications targeting specific groups. It took two years to get customer traction. Clients were skeptical that it was worth trying to convince customers to do anything besides spend 99 cents to download an app, says Magnuson. But persistence paid off for Appboy, whose client list now includes Jet.com, Delivery Hero, and SoundCloud. The average contract size for an Appboy customer is six figures. So far, the company has raised $42.5 million in total from venture capitalists. --Anna Hensel