SMS Sender Validation

Before sending your SMS Campaign, you must enter your Sender for validation.

To do this, you need to enter the Sender in Closum.

How to do this

1º - Click on Application

2º - Click on SMS

3º - Click on Register in the ‘Register Senders’ section

4º - Click on Add Sender

5 - Enter the sender you want to use

Importance of SMS Sender Validation

SMS sender validation is essential to ensure that messages sent are recognised, delivered correctly and convey credibility. Here are the main reasons why this validation is necessary:

Prevents SMS from being blocked by operators

• Many telecoms operators block messages sent by non-validated senders, as they can be considered spam or scams

• If validation is not carried out, the message may not be delivered to the recipient or may be marked as suspicious

Allows the name of the company to appear on the SMS sender

• Messages cannot be sent with a generic or short number, such as ‘38749’ or ‘+351912345678’, which reduces recipient confidence

• With validation, the company name can appear directly, such as ‘Closum’, giving the communication more credibility

Improves opening and response rates

• When customers recognise the sender, they are more likely to open and read the SMS.

Good Practices for SMS Sender Configuration

Choose a suitable sender name

• The name should be between 3 and 11 characters long (depending on the operator)

• Avoid spaces and special characters (!, ?, $, #, etc.)

• The name must clearly represent the company or brand (e.g. ‘Closum’, not ‘Promo123’)

Follow the rules of the operators

• Some operators do not accept generic names such as ‘Support’, “Service” or ‘Customer Service’.

• If the SMS is transactional (e.g. confirmation codes), a fixed numeric sender may be required.

Test the sender before sending in mass

• After validation, send tests to different numbers to ensure that the name appears correctly

• If the name is not displayed, check whether the operator is applying any display restrictions

Have a plan B in case validation fails

• If the operator refuses a sender, try an adjusted version (e.g. ‘ClosumPt’ instead of ‘Closum’)

• Use a validated landline number as an alternative if the name sender is not accepted

Keep the sender updated at all times

• Some operators require validation to be renewed after a certain period of time

• If there is a change in the company (change of name, merger, etc.), update the validated sender

Updated on: 10/07/2025