In the past, smartphone users had no choice but to hook into restrictive long term phone plans, but they’re now exploring more flexible arrangements.

According to a 2014 GSMA report on ‘The Mobile Economy, Asia-Pacific,’ markets in Southern Asia are predominantly prepaid where multiple SIM ownership is seen as commonplace. In fact, analysis from GSMA intelligence shows that users in developing markets own an average of two SIM cards in order to take advantage of the latest and most affordable prepaid tariffs.

The newly launched Hanoi-based OnOnPay, an app that lets users conveniently top up via mobile, is one startup taking advantage of this latest trend. “In Vietnam, 95 per cent of people are using prepaid and the mobile penetration is quite high. It’s the same situation for the neighboring markets, in Thailand, the Philippines, Malaysia and Myanmar. And it’s just something cultural: People really want the flexibility, they want to top up whenever they want and don’t want to engage with a fixed plan,” said founder Sỹ Phong Bùi.

He tells e27 that the preference for prepaid stems from the love for promotions. With fixed plans, users are limited to one SIM card with one telco but with prepaid, users can select whichever telco is offering a promotion at any given time.

OnOnPay sends notifications when balances are running low, schedules top-ups in line with big promotion dates and lets users add funds for several phone numbers at a time.

Having begun building their product since February 2015, the young startup has already signed on all five telcos in Vietnam and are in talks to increase collaboration with their partners. “When you have direct connections with telcos, you can get more information about subscriber accounts. For example, you can know in real-time the amount of money left in the customer’s account so you can send proactive notifications such as: ‘Do top up now to avoid losing your connection, and if you top up now you can get 10% off,” said Bùi.

Armed with five years of domain experience in the telecommunications space in France, Bùi is well-versed in deploying similar services for European telcos. After returning to Vietnam in 2010, he worked in the banking sector all the while yearning to return to the telecom space — but bided his time until the market was mature enough for online payments.

Within four months, OnOnPay has already picked up 600 early adopters and Bùi reveals his startup’s roadmap. “The plan is to tap into 10,000 active customers this year and 200,000 by the end of next year. We’ve already connected with all five telcos and are in talks with them to have direct connection. Viettel is one of the telcos we’re talking to and they have 47 per cent of all the market share.”

Bùi is running his 12-person team solo, with the help of two advisors from his telco days in France, but is looking to bring on a co-founder with experience in the business or technical realm. Having already secured a first round of angel investment, OnOnPay is looking to raise a seed round to acquire Vietnamese customers and support their move into neighboring markets. Their focus, said Bùi, is on rapid expansion as big players such as FreeCharge and PayTM are laying on the pressure.

They are looking to Thailand and Malaysia as their next markets and plan to move fast.