Yoyo Wallet, Europe’s fastest growing mobile payments app, raised £12 million ($15.3 million) in a Series B round, it announced on Monday. The deal was led by German retail giant Metro Group, and awaits approval from the U.K.’s Financial Conduct Authority.

The U.K.-based fintech app began life four years ago, servicing dozens of U.K. and Irish universities. It now allows its 400,000 registered users to pay for goods using their smartphones in over 1,700 outlets, including Caffé Nero and Planet Organic.

“Yoyo is now delivering proven benefits to a rapidly growing number of merchants and their customers in universities, corporate campuses and the High Street,” Alain Falys, Yoyo Wallet’s co-founder and chief executive officer, announced on Monday.

“This new funding will allow us to provide the benefits of customer identification and mobile engagement to a wider array of retailers, large and small, in the U.K. and across Europe. We could not have found a better combination of Investors to support us through this next stage of growth.”

The app is one of many mobile payment apps replacing physical payment, with its own personalized loyalty and rewards programs. It uses customer data to help retailers tailor rewards programs that appeal to individual consumers.

“Consumers are spending more than three hours a day on their smartphones and 40 percent buy more when subject to a personalized shopping experience,” Falys added. “Yoyo simply provides all retailers with an accessible way of tapping into these behaviors.”

Hansjörg Sage, general manager at the digital unit of Metro Group, said: “With its strong track record of deploying digital technology at the customer interface, Yoyo’s solution can have a meaningful positive impact on a wide spectrum of retail businesses, in particular in the food and beverage segment.

“As digitization becomes mainstream in hospitality, Yoyo’s technology is a strong candidate for currently untapped market segments. As part of our engagement, Metro intends to contribute to this deployment.”

James Hook, partner at Metro Group’s digital unit and to-be-elected board member of Yoyo Wallet, said: “We are delighted to be supporting Yoyo in its ambition to become the leading digital mobile payment and customer engagement platform.”

The fundraising also received backing from U.K. fund manager Woodford Investment Management, and tech-focused U.K investor Touchstone Innovations – the venture capital arm of Imperial College London.

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