SMS guidelines for Vietnam
SMS works differently in every country. See how it works in Vietnam.
MobiFone, Gmobile, VinaPhone, Vietnamobile, Viettel
You cannot send SMS to a landline destination number: the Twilio REST API will throw a 400 response with error code 21614, the message will not appear in the logs, and the account will not be charged.
You may use a global SMS-capable number to reach mobile phones in Vietnam; however the Sender ID will be changed to a numeric string in international format to ensure delivery.
Not all Vietnamese carriers support Unicode characters. Customers have reported better results when using only the basic ASCII character set in Vietnam.
Twilio strongly encourages customers to review proposed use cases with qualified legal counsel to ensure they comply with all applicable laws. The following are some general best practices:
- Get opt-in consent from each end user before sending any communication to them, particular for marketing or other non-essential communications.
- Only communicate during an end user's daytime hours unless it is urgent.
- SMS campaigns should support HELP/STOP messages, and similar messages, in the end user's local language.
- Do not contact end users on do-not-call or do-not-disturb registries.
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