As Vietnam’s homegrown super app, Zalo has outcompeted many overseas communication products over more than a decade and achieved extremely high penetration among Vietnamese internet users. Under regulations issued by Vietnam’s MIC, standard A2P SMS only supports one-way delivery. Enterprises commonly adopt a channel combination strategy of “Zalo first, SMS as backup” for business operations.
Zalo has nearly 77–80 million monthly active users and sends roughly 2 billion messages daily, with user penetration between 79% and 87%. In contrast, WhatsApp only holds 4%–6% local penetration and can hardly serve ordinary domestic end users. With Zalo Official Accounts (OA) and the ZNS notification service API, enterprises can handle two-way business communications including verification codes, order alerts and customer service interactions. Messages support richer presentation formats than traditional SMS, yet ZNS comes with monthly volume quotas, so capacity planning is required before launch.
Regulated by MIC and ABEI, standard Vietnamese A2P SMS does not support user replies. It also mandates display of registered alphanumeric brand Sender-ID within message content, and Sender-ID registration takes approximately five weeks. Therefore, SMS generally serves only as a fallback channel for critical alerts and verification codes targeting users without Zalo or under poor network conditions. Many government agencies also operate Zalo official accounts for public services, further cementing its status for commercial and public service communications. Enterprises entering Vietnam cannot copy the Europe and US model prioritizing WhatsApp; they need to adapt to the local Zalo ecosystem and pair it with SMS to achieve full population coverage.
