INDIA (IN)

Twilio fully supports all types of traffic to India, including promotional, transactional, and International Long Distance Operator (ILDO) messages. You must submit promotional or marketing messages between 09:00 and 21:00 local time; anything submitted outside this time will be processed the next day. Promotional messages sent using Sender IDs will be overwritten with a 6-digit short code (XX-NNNNNN), and messages sent to numbers registered in the do-not-disturb database will be blocked. You can find more information here: https://support.twilio.com/hc/en-us/articles/223134167-Limitations-sending-SMS-messages-to-Indian-mobile-devices

You should send transactional content such as alerts, banking, and OTPs through a carrier-approved transactional connection. To bypass the do-not-disturb database, you must:

1. Submit all your message templates for whitelisting.
2. Register a 6-character, no special characters, and all uppercase alphanumeric Sender ID.

Due to regulations, Sender IDs will be prefixed with an India 2-letter prefix source (YZ-ABCDEF) where Y connotes the service provider sending the SMS and Z connotes the telecom circle from which the SMS was sent.

Sending non-whitelisted content will result in delivery failure, and sending promotional or marketing content through the transactional connection will result in a penalty imposed by mobile operators. You must submit over-the-top (OTT) traffic originating outside India through a dedicated connection and not through conventional promotional or transactional connections. OTT messages need to go through mobile carriers' ILDO connections and have to be terminated with either a short code or a long number. Mobile carriers are actively blocking OTT messages submitted through non-authorized connections.

Twilio strongly encourages customers to review proposed use cases with qualified legal counsel to make sure that they comply with all applicable laws. The following are some general best practices:

1. Get opt-in consent from each end user before sending any communication to them, particular for marketing or other non-essential communications.
2. Only communicate during an end user's daytime hours unless it is urgent.
3. SMS campaigns should support HELP/STOP messages, and similar messages, in the end user's local language.
4. Do not contact end users on do-not-call or do-not-disturb registries.