Ringewald will join the company as vice president of software product management for the business, where he will help design software-based consumer products.

He has been chief technology officer for Boku, the mobile payments network that enables customers to purchase virtual goods using their phone numbers, since helping to found it nearly four years ago.

Before that Ringewald was a general manager and vice president of Amazon, where he led the development of the e-commerce giant's digital music site. Earlier in his career, he co-founded Accept.com, which pioneered person-to-person payments on the Internet.

At American Express he joins another former Boku staffer, David Yoo, who joined the card firm earlier this year to lead the commerce innovation team.

Josh Silverman, president, US consumer services business, Amex, says: "Erich will be instrumental in helping American Express turn ideas into innovative products and do so more quickly, - adding to the competitive advantage we already have as we connect buyers and sellers with an increasingly enhanced consumer experience."