It was Jorge Ruiz, Citibank's head of business development and digital banking for Latin America, who came up with the idea for Citi's first "hackathon."

Ruiz said his idea was based on the hackathons organized by Facebook and other tech companies, typically where groups of software developers would spend a few days locked in an enclosed space together for round-the-clock collaborations.

"They will give them food; they will give them Red Bull, and they will develop something throughout the weekend," Ruiz says. "It's a very unique way of really leveraging brilliant minds, and doing it in a fast-track way."

Formally called the Citi Mobile Challenge LatAm 2014, Citi's hackathon kicked off in April, with invited participants submitting concepts in May and finalists scheduled to compete through the first week of June. Winning developers will split up $50,000 in prize money. Ruiz says. Contestants from 10 countries, representatives of about 70 companies plus 30 individuals, are competing. Ruiz says the event, and the mobile banking app ideas that come from it, will be transformative.

"What we're going to have after this is probably going to transform the way the industry seeks and manages technology," he says. Financial firms usually buy or develop technology, but they like to own the technology. "They like to sometimes even reinvent the wheel," he says.

"In this case, what I'm trying to do is to say: 'Hey, there's a lot out there; there's a lot of people who want to partner with us, and want to work with us—let's do it,'" Ruiz says. "The whole point here is to see what the community is doing; what the developers in each of the markets are doing, leverage that in a very fast way, and hopefully not just launch this in the market where it's been developed, but in multiple markets."

In 2013, Ruiz led 34 major digital deployments at Citi, including mobile, tablet and online solutions. Those include the Beneficios de Citi app, which provides bank customers with "augmented reality" technology to scan their surroundings with a smartphone or tablet camera to identify nearby establishments offering discounts or promotions. The app, now available in 11 Latin American countries, also uses interactive mapping and optional alerts, and provides information on branch and ATM locations.

Ruiz also led the design and implementation of Citi Mobile Collect in the Dominican Republic, which allows small businesses that don't typically use banks, such as grocery stores, to open an account with Citi partner Banco ADOPEM, a microfinance institution, and replace their cash payments with mobile transactions. He is also co-founder of the social network, which supports charities in more than 20 countries.