India: SMS Features & Restrictions

By default all SMS are categorised as promotional, and subject to the following limitations:

-Sender IDs are altered to ensure delivery

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.

-SMS are blocked to numbers registered under the Do Not Call registry

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.

-SMS can only be delivered from 9am to 9pm (local India time)

Due to local regulations, promotional SMS sent after 9pm and before 9am will be queued until 9am, when the time constraint are unblocked. Queued SMS will be charged as usual.

Transactional traffic registration

If your messages carry transactional content (e.g. OTP and notification), pre-registering your account will allow you to deliver messages at any time, outside of this time limitation.

The pre-registration process is different for Domestic and International brand clients:

Domestic brand clients

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

The registered Alpha SenderID 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 SenderID)
You can find a full list of prefixes here: India Pre-registered SenderID Prefixes

Please note that Opt-in info is required for customers who intend to send non-transactional SMS through domestic routing.

International brand clients:

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

Other features/restrictions:


Unicode is supported

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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