Online home renovation and design giant Houzz didn't start out with a plan to enter the Indian market. Instead, the Indian market came to Houzz, which is based in Palo Alto, California. The site, which draws some 40 million visitors each month, became aware that a million customers and more than 50,000 service providers in India had signed up to use the site. Responding to the strong interest, Houzz launched a custom site for the Indian market in January of this year. "These homeowners and professionals expressed strong interest in helping us localize Houzz for India, and we're excited to work with them to further tailor the experience," says Adi Tatarko, CEO and co-founder of Houzz, which made the CNBC Disruptor 50 list for the third straight year.

Houzz is one of several companies on this year's Disruptor list focused on India, reflecting the growing importance of the South Asian country of 1.3 billion people as a strong consumer market in its own right. India has a fast-growing economy for a large country, reaching 7.1 percent GDP growth last year. Although a majority of Indians remains poor, a large middle class with disposable income has emerged. Estimates of the size of this new Indian middle class run as high as 300 million. That's more than enough to draw the attention of the U.S. Internet giants as well as domestic start-ups.

The Gateway of India Monument in Mumbai Shanna Baker | Getty Images

Ezetap benefited from the chaotic efforts by the Indian government last November to take the most popular denomination bank notes out of circulation to combat corruption. Delays in exchanging old 500- and 1000-rupee bills for new ones led to cash shortages and long queues at banks. The crisis drove many Indians, who had mostly depended on cash transactions, to electronic payment services like Ezetap. "In 30 days our numbers jumped 50 percent to 100 percent," says Bose. Ezetap distributed 300,000 point-of-sale devices in the fourth quarter of 2016. "What could take five years ended up taking five months." Bose says Ezetap now handles payments at a run rate of $2 billion a year, more than double the volume when it made last year's list.

Cultural nuances

Those who enter the Indian market agree that adjusting to the market is essential for success. Indian states can have wildly different regulations, various degrees of bureaucracy and different languages in addition to English. Web applications need to be optimized for slower internet speeds in some parts of India. Udacity, an online learning company based in Mountain View, California, was founded by Stanford University artificial intelligence professor Sebastian Thrun, who created Google's autonomous vehicle program. Udacity offers technical courses to 4 million students in 168 countries, including India, its second-largest English-language market after the United States. Offerings include the mobile operating systems Android and iOS, self-driving vehicles and artificial intelligence. Udacity opened offices in New Delhi and Bangalore, India, to have a local presence and better support its students. The company says its advantage in a crowded online educational market is its close cooperation with industry leaders in developing courses. Graduates earn a "nanodegree" with the exact knowledge companies want their employees to have.

Sebastian Thrun, founder and CEO of Udacity, launches Android Nanodegree in Bangalore, India, in September 2015. Kiran Manjunath | AFP | Getty Images