Viettel Tammi Reaches 20 Million Users as Daily Use Becomes the Next Test

A Fast Start Beyond Viettel's Own Customers

Viettel Telecom announced on October 27 that its Tammi communications app had reached 20 million users less than three months after its public launch in August. About 10% used phone numbers from other mobile networks, including VinaPhone and MobiFone, putting the number of users outside Viettel's subscriber base at roughly 2 million.

The company also reported a daily active user to monthly active user ratio of nearly 30% for October. The figures place that activity measurement in October 2026. Viettel did not publish the underlying daily or monthly active user totals, leaving the size of its regularly active audience undisclosed.

Tammi combines messaging, calls and online meetings with payments, transport bookings, deliveries and telecommunications account management. Its growth comes with practical incentives: Viettel subscribers receive free mobile data when using the app, while other benefits include 5GB of Viettel Cloud storage and free meetings connecting up to 100 locations.

Viettel is also making verified identity part of its pitch. Tammi supports links to Vietnam's VNeID electronic identity system and verified organisational accounts, aiming to help people recognise genuine messages from businesses, schools and public agencies.

The result is an ambitious attempt to turn a telecommunications customer network into a broader digital services platform. Reaching people quickly is the first part of that effort. Getting them to return for conversations, work and everyday services is the next.

From Internal Release to Public Launch

Tammi appeared in app stores in April for internal use before being introduced to the public in August. The distinction explains how an application already available for several months could reach its announced milestone within less than three months of its official market launch.

• April: Tammi was placed in app stores for internal use.
• August: Viettel introduced the application to the public.
• October: Viettel recorded a daily active user to monthly active user ratio of nearly 30%.
• October 27: Viettel Telecom announced that Tammi had reached 20 million users.

Viettel says Tammi repeatedly appeared among the leading free applications by downloads on both Apple's App Store and Google Play in Vietnam after its launch. Those rankings gave the application visibility alongside established messaging services competing for the same users.

The launch also drew on a distribution advantage already inside Viettel's business: an existing mobile network, a large customer base and a local service presence. Those resources give the company several ways to introduce Tammi to people who already use its telecommunications services.

What the Usage Figures Tell Readers

Viettel's 20 million figure describes the platform's reported user base. The nearly 30% activity ratio answers a different question: how large the daily active audience is compared with the audience active during a month.

For a simple example, if an app had 100 monthly active users, a ratio near 30% would mean roughly 30 daily active users relative to that monthly group. The people active on one day may differ from those active on another.

The calculation uses monthly active users as its starting point. Applying 30% directly to Tammi's entire 20 million user base would require knowing how many of those people were active during October, a figure Viettel has not released.

The network breakdown offers another useful comparison. At approximately 10% of 20 million, customers of other operators account for about 2 million users, leaving roughly 18 million associated with Viettel numbers. Tammi therefore has an audience beyond its parent network, while its own subscribers still account for about nine out of every 10 users.

For a communications service, returning use matters because people need their contacts and groups to be available there. A parent may open an app for a school notice, while an employee may use it for a work meeting. Building a daily habit means giving those people reasons to return between such specific tasks.

Free Data and Meetings Lower the Entry Cost

Viettel subscribers are exempt from mobile data charges when using Tammi under the applicable policy. That benefit reduces the cost of trying the service and of continuing to use it away from a Wi-Fi connection.

The distinction between subscriber groups matters. Tammi accepts users from other mobile operators, but the announced mobile data exemption applies to Viettel subscribers. People joining with another operator's number face their own network's data arrangements.

The meeting service allows up to 100 connection points for as long as 120 minutes per free session. A connection point is a device or location joining the meeting, so a room with several people using one connection can count as a single point.

The 5GB of free Viettel Cloud storage adds a place to keep files alongside communications tools. Together, storage, meetings and messaging give work groups and education users several connected reasons to open the application.

These benefits also show how closely Tammi's early growth strategy is tied to Viettel's existing infrastructure. Mobile connectivity, cloud storage and communication services are being offered together, rather than requiring users to arrange each separately.

A Single App for More Daily Tasks

Viettel is developing Tammi as a super app, a term for an application that brings several types of services into one place. In Tammi's case, that means combining conversations with practical tools such as payments, ride bookings, deliveries and management of telecommunications services.

The approach gives Viettel more opportunities to attract repeat visits. Someone checking a mobile service account might also see a message, while someone joining a meeting could later use a payment or delivery function.

Tammi also includes an artificial intelligence assistant inside its chat interface. Viettel describes it as a tool for finding information, answering questions and handling everyday tasks. AI tools also support noise filtering, which can make speech easier to hear during calls.

Hoang Trung Thanh, general director of Viettel Telecom, described the company's intended role for the application:

Vietnamese people do not lack applications for communication. Therefore, we do not want simply to create another messaging app, but aim to build a digital connection platform where people can communicate, interact with organisations and access essential services.

That ambition fits Viettel's expansion from telecommunications into digital technology. Tammi gives the company a place to combine its connectivity business with services used in education, work and daily life.

Verified Accounts for Schools, Businesses and Agencies

Tammi OA, short for Official Account, provides accounts for businesses, public agencies and other organisations. Viettel presents these accounts as channels for notices, customer support, information exchanges and digital services.

Verification addresses a familiar problem: a convincing account name and profile photograph can make an impersonator look genuine. A parent receiving a tuition notice or a customer receiving a payment request needs a reliable way to identify the organisation behind it.

Viettel says its local network, extending to villages and hamlets, can support direct verification of organisational accounts. This gives its physical presence a role in a service that otherwise operates through a phone screen.

Tammi OA can also connect with local integrated operations centres, known as IOCs. These are central systems used by local authorities to bring information and operational management together. Connecting an official account with such a system creates a route for public agencies to communicate with residents through the application.

The practical attraction is a recognisable channel for institutional messages. For Tammi, those channels could also create recurring use when residents need updates or services from an organisation they already deal with.

How Tammi Protects Accounts and Conversations

Viettel says Tammi uses phone number verification and a one time password, or OTP, during account authentication. The app also supports a connection to VNeID to strengthen identity verification and requires users to authenticate again when changing the device used to log in.

These measures address control of the account: who is registering, who is signing in and whether a new device should be trusted. Verified organisational accounts address another part of the problem by identifying the institution sending a message.

For conversation content, Viettel says Tammi applies end to end encryption to supported forms of communication, including personal conversations. End to end encryption scrambles messages so they can be read at the communicating endpoints, rather than along the route between them.

Viettel's description limits the encryption claim to supported communications. The company also lists privacy controls that let users lock or hide conversations with a personal PIN and set messages to delete automatically.

Group administrators can restrict actions such as downloading files, forwarding messages and recording or capturing screens. These controls give groups more ways to manage how information is shared, alongside the protections applied to accounts and message content.

The Test Is Whether Users Keep Returning

Tammi enters a Vietnamese messaging market where people already have established contacts, family conversations and work groups on other services. Moving a conversation often requires several people to change their habits together.

Some users may initially join because a school group, workplace or promotional benefit gives them a particular reason to do so. Viettel's combination of official accounts, meetings, services and free data creates several possible routes from occasional use to a more regular habit.

Thanh described the 20 million milestone as a beginning and set out how he believes Tammi's longer term performance should be judged:

Tammi's long term success will be assessed through regular use, users' trust and the practical value the platform brings.

The next useful measures will therefore be how many people remain active and how frequently they return. Viettel's disclosed figures show rapid reach and an initial measure of engagement. Continued use will determine how large a role Tammi earns in everyday communication.

Key Points

• Viettel Telecom announced 20 million Tammi users on October 27, less than three months after its public launch in August.
• About 10% use other mobile networks, equivalent to roughly 2 million people.
• The October daily active user to monthly active user ratio was nearly 30%; the underlying active user totals were not released.
• Benefits include free mobile data for Viettel subscribers, 5GB of cloud storage and free meetings with up to 100 connection points for 120 minutes.
• Tammi combines communications, everyday services, an AI assistant and verified organisational accounts.
• Viettel identifies regular use, trust and practical value as the measures of lasting success.