India: SMS Features & Restrictions

India is a very complex market and there are a number of different regulations and restrictions you must comply with in order to send SMS here.


Traffic Type Content Allowed Sender ID Restrictions/Regulation
Domestic Transactional Transactional traffic, OTP 6 digit alpha (not alphanumeric) with preregistration No restrictions. 24/7 delivery without NDNC restrictions.  

The registered Alpha Sender ID will be added with 2 letters as a prefix, depending on which carrier was used to deliver the SMS to the final operator or 2 random numbers; e.g. MD-XXXXXX (where XXXXXX is the registered Sender ID)
Domestic Promotional (none opted in)

Promo/Marketing content

Sender ID not supported and will be change to a random short code Promo sms will be blocked to numbers registered in NDNC as per TRAI regulation.

Promo sms are only delivered between 9am-9pm IST time.

SMS outside the time range will be queued and delivered next day.
International (transactional/Opted-in Promo) International originated transactional content & Opt-in Promo content. (If client registered in India,but sms originated outside India, will be identified as International traffic).  Sender ID not supported and will be change to a random short/long virtual number

SMS Delivered 24/7 via International route.

No restrictions for NDNC listed numbers.

 For opted in promo sms, same Regulation apply as in  for Domestic Promotional(Opted in) listed below.

International Promotional (none opted in) No such origination at present moment NA NA
Domestic Promotional (opted in) This traffic can only be routed via transactional bind with opted in confirmations from each subscriber MSISDN 6 digit alpha (not alphanumeric) with pregistration 24/7 delivery and without NDNC restriction.

However, handling party (customer) of the promo content must have subscriber opted in consent per each MSISDN and should provide the information to the providers handling the traffic either upfront or on demand in an event if the termination party gets a complaint from a mobile operator (mobile subscriber complaining to operator for receiving a promo content) as proof the subscriber has given consent to receive promo content. Failing to do so (not defined the actual time period) provider will be liable for penalty charges depend on the number of violations. Please refer to Schedule IV, Article 10 --> for details. Need to have contractual provisions in order to accept the penalty charges in case of violation.


Sender ID

Domestic brand clients with a local entity can register through, for volumes exceeding 25k SMS/month.

The below information is required:

  • A 6-letters alpha sender ID (normally your brand name or abbreviation)
  • SMS templates

SenderID will be prefixed with 2 letters depending on which carrier was used to deliver the SMS to the final operator. Full list of prefixes here: India Pre-registered SenderID Prefixes

Alpha Sender ID is not supported for International customers, and will be changed to a random short code. For more information please contact your Account manager or email to

Any unregistered sender ID is overwritten with a local short code as required by Indian regulations, whether the destination number is registered on the NDNC list or not.


Do Not Call registry(NDNC)

Non-Optin Promo Messages sent to numbers registered in the Indian NDNC (National Do Not Call registry) list will be blocked. To know if a number is registered withi then NDNC list, you can use the following link: Telecom Regulatory Authority of India


Limitation to avoid potential SMS flooding

Local regulations specify limitations to the number of messages that can be sent to the same number:

  • More than 6 messages to the same destination number within an hour with the same sender or text may be blocked
  • Users may not be able to receive more than a total of 200 SMS per day across all incoming streams.



Other features/restrictions: 


Unicode is supported.

Delivery Receipts:
Handset delivery receipts are reliable.

Traffic restriction by political reason:

Messages towards Jammu and Kashmir networks (example, 405/55 - Airtel J&K) will be blocked by the government due to political sensitivity.

Please also note that political SMS are prohibited during election period throughout the country.


Global SMS Features Overview (Outbound only)

Global SMS Numbers Features Overview


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