Sender ID definition

A sender ID is an alphanumeric string, that can be used as the "from" address for SMS text messages that are sent. A character-based sender ID, usually the brand or company name, is commonly used for SMS programs that are one-way (outbound only).  

The SMS protocol technically limits the sender ID to max. 11 characters.

The alphanumeric sender ID gives the sender the ability to send messages using a custom ID constructed from a combination of alpha (a-z, A-Z) and numeric (0-9) characters, including spaces/blanks. Any other characters (e.g. dots) should be avoided. Using a SenderID makes the sender of the SMS identifiable to the recipient of the message. has adopted the general restrictions in some countries where alphanumeric SenderID is not supported by default. Some of them require a pre-registration. To learn more about these restrictions regarding SenderID, please visit International SenderID Regulations and Requirements (list of countries). You can determine which countries support alphanumeric SenderID.


Alphabetical sender IDs cannot be replied to and hence they cannot be used for 2-way-communication. A short or long code is required to be used for inbound messages. The capability for a dynamic alphanumeric Sender ID is based on country and carrier requirements and thus cannot be guaranteed for each country. For more information on which countries can use sender ID for SMS traffic, please contact your Account Manager.

Please note that when using a rented long code as a sender ID, it needs to be used in the international format but without the leading plus sign (+)
Example for Cyprus: 35794585001

How to use a Sender ID

When composing an SMS campaign, simply use this field to fill in your desired Sender ID:

If you regularly use a specific Sender ID, you can configure this Sender ID in your account settings and it will be used by default:

Our general recommendation is to always use your own Sender ID instead of using "SMSto" or generic values like "Info". Using a non-unique Sender ID can degrade delivery success of your messages.

If you have any questions, please send an email to