GitHub, the 'Facebook for programmers,' has quietly built up an enterprise business that accounts for half its sales

GitHub may have a reputation as a hub for up-and-coming young coders, but the $2 billion company has a secret user base driving its success: corporations.

About half of GitHub's $200 million in annual revenue comes from businesses, according to chief strategy officer Julio Avalos. And that number is growing as more and more software developers who learned to code on GitHub's site get hired by corporations and encourage their new companies to use GitHub as well.

The distinction between "enterprise versus consumer is going away," Avalos said.

GitHub offers its core services - project spaces, code libraries, and forums - for free to anyone who wants to create open-source software. But for corporations who are willing to pay for a service it calls GitHub Enterprise, the company offers additional features, including private workspaces, 24-7 support, and more dynamic cloud hosting options.

The company offers another paid service that allows users to keep their code private. Subscription fees from that service account for the other half of its total revenue.

GitHub first launched its enterprise service as a way to allow companies to store code on their own servers, rather than in GitHub's data centers, Avalos told Business Insider. This spring, GitHub added on an option that allows corporate customers to store their work on the major cloud services, including Amazon Web Services and Microsoft Azure.

Its enterprise service has proven to be popular. In its recently released user report, the company said 52% of Fortune 50 corporations are GitHub Enterprise customers, as are 45% of those in the Fortune 100. Microsoft and Facebook run the two largest projects on GitHub's site.

The company's enterprise push comes as it is rumored to be preparing for an IPO. With investors likely eager for a growth story, GitHub could be pressed to offer one.

Avalos sees some opportunities for the company. More than half of the Fortune 100 aren't yet GitHub customers, so there's room for growth there, he said. And he noted that the company has set a major goal of expanding its international reach, particularly to China.

But Avalos acknowledges the company faces some growth challenges ahead.

There are only about 21 million software developers in the world, according to market research firm IDC. GitHub already has 24 million users, although many of them likely aren't actual coders.

Regardless, there just aren't enough software developers globally, Avalos said, adding that GitHub needs to help produce more. He thinks it's GitHub's responsibility to explore ways to reach populations who might not think about computer science as a viable career path for themselves.

GitHub can help, particularly in the US, by "playing a role in education and on-ramping," he said.