Financial institutions must often consider mobile features that don't integrate smoothly with their existing app, leading to the difficult decision of offering different branded apps for different use cases.

One of the earliest examples was mobile check deposit, which some financial institutions saw as enough of a differentiator that they were willing to push out a second app just for this service. In the case of San Antonio Federal Credit Union, the must-have service is mobile card controls, and the credit union is drawing inspiration from Facebook in how it brings the service to market.

The model is Facebook Messenger, which Facebook split off from its primary app in 2014. Though users must install two separate apps, Facebook has linked them together to create a sense of unity.

"We wanted a mobile-first approach … [but] our own credit union mobile app was somewhat limited. We don't have push alerts and our vendor couldn't provide it to us," Adele Glenn, emerging channels innovation architect at San Antonio Federal, said during a presentation at SourceMedia's annual PayThink conference, taking place this week in New Orleans.

Push alerts are a vital part of the security philosophy behind the credit union's decision to offer mobile card controls. The credit union is testing a "subordinate app" model where it will prompt users to download a second app when they tap on the Card Control tile within the credit union's main app.

Once both apps are installed, "it will send them back and forth, the same way Facebook and Facebook Messenger work," Glenn said. "It's a seamless experience, but again, in two separate apps."

The card control function itself is from Ondot Solutions, which various vendors resell under their own branding; Fiserv calls it CardValet, Glenn said.

The Card Control app lets members turn their cards on or off at any time. It also allows users to set spending thresholds and limit spending to certain merchant categories (Glenn noted that these limits can be removed through the app as well, so it is "not the best diet tool" for someone who wants to block spending at restaurants).

Users can also limit spending by location. Glenn noted that she has two cards from San Antonio Federal that she brought with her to New Orleans, but only one had Card Control enabled. When she tried to use the other one, it was declined because the credit union considered her location suspicious.

She then switched to the other card, and used Card Control to set New Orleans as an approved location. The transaction on that card went through.

"All of those parameters are in there. We are turning them over to the members ... instead of us having to guess on the back end what your behavior is and what's out of band," Glenn said.

This also allowed the credit union to raise its default threshold for spending on its cards while giving members the ability to set a lower limit through the app.

The technology is being beta tested with 250 members, but it is proving so popular among testers that San Antonio Federal has a waitlist of more than 800 potential users.

The credit union plans to roll out the app to all members by the end of this year, and projects enrollment of 4,000 people in the first quarter of 2017. By the end of the first year, it predicts up to 12,000 people will sign up.

Overall, San Antonio Federal expects a 20% reduction in actual fraud losses, Glenn said.

Though the credit union took pains to make the new app appear as a seamless part of its main banking app, some beta users like that Card Control is a separate app since they can "jump right to it," Glenn said. "They don't see it as the same mindset as mobile banking."

The credit union predicts Card Control will have other uses besides flagging fraud. The app's ability to limit spending to certain merchant categories makes it appealing for corporate card accounts, Glenn said; there is already a feature that lets users scan receipts for reimbursement.

The next step is personal financial management.

"We actually are looking at integrating this with our [Geezeo] PFM tool … so that if you're overspending, we'll actually start declining on your behalf so you can stay within budget," Glenn said.