The number of people using Zalo, an instant messaging app developed by local technology company VNG, has hit 50 million, local media reported on Friday, citing the developer.
That is equivalent to more than half of Vietnam's population and an increase of over 66 percent from the middle of last year.
Since the data was released by the company itself, it is difficult to independently verify the impressive number.
Launched in 2012, Zalo has cooperated with several government agencies in providing people with accesses to search for administrative information such as vaccination and appointments, besides calling, messaging and booking air tickets.
Zalo is one of five local businesses which are providing over-the-top contents, the official technical term for the delivery of audio, video and other media over the Internet, in Vietnam.
Three telecom giants MobiFone, Viettel and VinaPhone launched their services last year, besides Hanoi-based Internet security firm Bkav, according to news website ICTNews.
Other than Zalo, Viettel is the only operator to have reported its number of Mocha users, which was estimated at around 3 million this month, the website said.
Foreign giants such as Facebook Messenger, Line, Viber and WhatsApp are also operative in Vietnam, but their number of users are not regularly released.
Of all the operators, Japan's Viber and South Korea's Kakao Talk and Line once officially launched their services here, but all pulled out reportedly due to harsh competition from local businesses.
Viber was the last one to close its local office in July last year and moved to the Philippines, after more than one year of operation with around 23 million users.