Ten years ago he cofounded Zocdoc, an online service that allows individuals to find a doctor and book an appointment as early as in 24 hours. The New York-based company does for physician appointments what Expedia (EXPE) and Hotels.com do for booking travel and hotels.

“The thinking is that in the long run, health care needs to be as convenient as calling a car or ordering something online,” says Kharraz, who for years was a practicing physician before becoming an entrepreneur. “There needs to be a completely seamless experience so that you can focus all your energy on getting better, instead of how to actually get in front of a doctor.”

Zocdoc’s services are available all across the United States. More than six million patients use Zocdoc every month and are able to book more than 1,800 different types of medical procedures across 50 specialties. A Zocdoc user typically gets to see a physician within 24 hours.

Kharraz says it’s a win-win for doctors and patients. He says once patients use Zocdoc they are “repeat customers.” Doctors pay a flat yearly fee of $3,000 and “love the service,” according to Kharraz because “it improves the way their business works, making sure they see patients every hour of the day that they’re available.”