Viettel Tammi app surpasses 5 million users.
This impressive growth stems from meeting the practical needs of Vietnamese people, including seamless communication (free calls and text messages, high-quality, smooth video calls thanks to AI applications, and phone-to-app functionality), along with nearly 50 integrated features in one application and numerous benefits for users.
Viettel Telecom, the telecommunications corporation of Viettel, has just announced that its Viettel Tammi application has surpassed 5 million users shortly after its launch. This impressive result demonstrates the positive reception from customers and marks the fastest growth rate for an OTT application in Vietnam.
Unlike Viettel's previous standalone applications, Tammi acts as a super-app layer, integrating nearly 50 services into a single interface, powered by an intelligent AI agent. Since its internal testing and launch, among the five core features initially introduced, Tammi has received the highest user ratings for its call, chat, and meeting capabilities.
Accordingly, Tammi addresses common limitations of internet calls such as stuttering, lag, loss of sound, or quality degradation when the connection is unstable. Unlike OTT platforms that operate separately from telecommunications infrastructure, Tammi combines the OTT service layer with Viettel's domestic network, and operates on core technological capabilities owned by Viettel, optimizing processing speed—a crucial factor in ensuring the quality of free calls.
One of Viettel Tammi's distinguishing features is cross-app-to-phone and phone-to-app calling, allowing Tammi users to call regular phone numbers that haven't installed the app, and vice versa. This feature extends the OTT connection range beyond the community of users who have installed the same app, and also supports users in situations such as weak mobile signal but with Wi-Fi available, or when roaming connections are interrupted.
Another notable feature is online conferencing. Tammi supports group video calls with up to 100 participants simultaneously, with a free duration of up to 120 minutes, 2-3 times longer than the typical 40-60 minutes offered by other online meeting applications; fully meeting the needs of everything from classrooms to business conferences.
Tammi was first introduced by Viettel at MWC Barcelona in March 2026 before entering an internal testing phase in Vietnam in June 2026. Reaching 5 million users marks the beginning of Viettel's vision to make Tammi a communication and digital lifestyle platform developed by Vietnamese people, with calling and chatting as core capabilities to form daily usage habits for users.