Now Stripe is looking to expand further outside the U.S., and is prepping for its entrance in Latin America and Southeast Asia, said John Collison, who co-founded the San Francisco-based company with his brother Patrick in 2010.
The start-up, which competes with PayPal's Braintree service and to some degree with Square, already operates in Europe, Australia and Canada.
In moving into emerging markets, Stripe has a competitive advantage, because its payment technology handles transactions in 139 currencies, Collison said. Credit cards, China's Alipay, checking accounts and bitcoin are all fair game.
The gap "between Stripe and other businesses widens as you go international," Collison said in an interview Wednesday at the Collision conference in Las Vegas.
Stripe, which raised $70 million in December and a total of about $190 million to date, provides software that lets mobile apps and commerce sites embed a payments system by adding just a few lines of code. Stripe charges 2.9 percent plus 30 cents for every transaction.
Like many Silicon Valley tech companies, Stripe got its initial traction by signing up other start-ups to use its product. Early adopters turned into evangelists, helping the company win bigger deals. Customers include crowdfunding site Kickstarter and software developers Salesforce.com and Splunk.
Stripe's international expansion is focused on both helping U.S. customers collect payments in more currencies and providing tools to businesses in countries where online payment options hardly exist.
As for Stripe's continued U.S. growth, Collison said that it is working with big companies that are adding commerce apps and services. For example, Wal-Mart picked Stripe for an online subscription service called Goodies.co in 2013.
"We're not doing huge rip and replace deals," Collison said. "But a lot of companies are using us when they do new stuff."