PayPay is one of SoftBank Group founder Masayoshi Son’s success stories, going from zero to more than 60 million users in five years. The payments app now seeks to keep its pace of double-digit growth with help from other SoftBank portfolio companies, according to its co-chief operating officer.

Tokyo-based PayPay propelled itself to prominence in the country’s fragmented cashless payments landscape, thanks to aggressive subsidies and SoftBank’s support in signing on merchants around Japan. It spent ¥10 billion in a cashback campaign in 10 days shortly after its 2018 debut, winning millions of users who crashed PayPay’s system multiple times.

Seen to be next in SoftBank’s initial public offering pipeline, the startup now holds two-thirds’ share in QR-code payments in a country where cash remains king. A partnership with Japan’s Line messaging service, under SoftBank’s telecom arm, would help PayPay win another 30 million users in the coming years, according to co-chief operating officer Masamichi Yasuda.