Mikkel Svane, Alexander Aghassipour, and Morten Primdahl founded software provider Zendesk to help customer service keep up with the cloud. Zendesk's software assists companies in managing customer-service requests that come in from a variety of channels, including email, the Web, social media, and the old-fashioned telephone. The company also has a variety of apps that companies can embed in their websites. However, the customer-service software industry has relatively low barriers to entry, so Zendesk has many competitors, including Atlassian, which raised nearly $500 million in preparation for its IPO at the end of 2015. But Zendesk believes that its competitive advantage is software that makes intercompany communication easier. Note: employee count as of Dec. 31, 2015

When Renaud Laplanche launched Lending Club, the online lending industry was still relatively new. Today, Lending Club is faced with an onslaught of competitors, such as BondStreet and Funding Circle, and the online lending industry is facing more scrutiny from both the Treasury Department and the Consumer Financial Protection Bureau. But by acting as an intermediary between lenders and borrowers (and thus getting paid only through transactional fees, not interest), Lending Club is confident that it is staying on the right side of the industry. To keep up with competitors, Lending Club continues to look for ways to broaden its loan product offerings. Note: employee count as of Dec. 31, 2015

GrubHub CEO Matt Maloney told Inc. that the company was born out of frustration at "the lack of dinner options as well as the pain in the ass of calling restaurants and reading our credit cards." Today, GrubHub ensures that a lack of options is the last thing diners have to worry about. GrubHub currently works with more than 40,000 restaurants, displaying their menus on its website and providing a way for customers to order food online. The company was able to successfully ward off one competitor--Seamless--after the two merged in 2013. But now GrubHub faces new competition from companies like Uber, which want to take a bite out of its revenue after seeing see how lucrative the food-delivery business can be. To maintain its status as a market leader, GrubHub is continuously looking for new restaurants to add to its network. Note: employee count as of Dec. 31, 2015

When Manuel Mehos launched Green Bancorp in 2006, he didn't choose the company's name because he was trying to be environmentally friendly. Rather, the commercial banking company wanted a simple, easy-to-remember moniker associated with money. Soon, Green Bancorp realized its name struck a nerve with eco-conscious customers, and pivoted. These days, the company markets itself on its website as "the bank that local businesses and consumers turn to first for good financial solutions that are environmentally responsible." While the company has been profitable for the past few years, it acknowledges that historically low interest rates have helped its revenue growth. Rate hikes, plus any hits to the Texas economy (where the majority of the company's customers are located), could hurt Green Bancorp. To compete with national banks, Green Bancorp touts its personalized services, and its history of helping Texas entrepreneurs grow their businesses. Note: employee count as of Dec. 31, 2015

Kip Tindell, John Mullen, and Garrett Boone got the idea for the Container Store after they noticed that many department stores lacked a solid selection of high-quality organizational products. Today, the Container Store sells a variety of boxes, crates, trays, and  filing systems in retail outlets across the country. The Container Store touts its commitments to customer service and employee well being, as well as churning a profit, as the keys to its success. But because it sells predominately discretionary items--that is, items that customers don't view as an essential part of their lifestyle--the company could find its revenue shrinking in an economic downturn (as it did during the 2007-09 recession). Still, the Container Store believes that its loyal customers will carry it through tough economic times.