In the recent past Zalo announced it had reached 15 million users, with 185 million messages delivered daily through its system and up five million users compared to March 2014.

Viber also claimed its users amounted to 12 million as of March.

Zalo and Viber are the two leading OTT service providers in the domestic market.

Back in mid-February 2014, Garena (registered in Singapore but with headquarters in Bangkok) made its foray into Vietnam with the launch of its BeeTalk app.

In mid-April, Bkav – Vietnam’s leading Internet security firm – rolled out its newest product Btalk. It has only managed to attract just over 100,000 users in its three months since launching.

Leading telecoms Viettel, MobiFone and VinaPhone have also reportedly claimed they are ready to offer OTT services, but “now is not the right time for such a launch”.

“OTT services are not having a drastic effect on the revenues of mobile service providers, which is why we have yet to jump into this field,” said a source from one of these leading telecoms.

While the top market players have yet to enter the race, the competition between existing OTT service providers is becoming much more severe.

Industry experts have said that unique services and solutions are key to providers getting the upper hand.

To strengthen its position, Viber has launched the Viber Out package, that allows uses to even call fixed telephone numbers very cheaply, for just VND400 per minute.

For its part, Zalo has rolled out its Zalo 2.0 version which includes marked changes to its interface and functionality, commensurate with its continuous product innovations.

Newcomer BeeTalk has reportedly made quite a splash through its marketing and promotions that have included outdoor billboards and brand ambassadors.

Nguyen The Tan, deputy general director of VC Corp, owner of the Zalo app, said “Competition between OTT service providers is not only concentrated on new innovative functions, but also transmission stability. Businesses that are consistent in providing basic functionality will ultimately succeed.”

According to Nguyen Tu Hoang, vice chairman of Bkav (owner of Btalk), OTT software products are very similar in terms of their functions, so to gain market share amid high competition, newcomers need to have a breakthrough development strategy.

“Stable quality and new experiences are crucial in helping gain users over the long-term,” Hoang added.

He also said that Btalk aims to grow into a market leader in OTT services provision over the next few years, before launching value-added services to further monetise its product.

According to Vuong Quang Khai, a leader at Zalo, advertising that target specific customer segments, value-added services (games, tone music, live pictures, etc.), and e-commerce are great ways for service providers to generate more revenue.

Khai forecasted that e-commerce would enjoy a development boom with OTT, but admitted that it would take time to realise this goal.