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Documents Required and Instructions to Register Your Alphanumeric Sender ID in Mexico

Before we begin

Due to regulatory requirements, there is sometimes a need for documents to be signed by customers to ensure that registrations are done on behalf of customers that have the right to use the Sender ID. This serves to ensure that traffic is coming from legitimate sources and minimizes any potential misuse.

This article outlines the documentation requirements for a pre-registration of a financial and/or alcohol-related Sender ID in Mexico.


To register your Alphanumeric Sender ID, the Mexico network operators require that you provide the following document: 

  • Letters of Authorization for financial and/or alcohol-related Sender ID Registration 
  • Telcel Template
  • Telefonica Template

To get you up and running as quickly as possible, please fill out the documents completely and accurately and provide any other required information. Use the examples provided for guidance. Note that mobile network carriers are very strict about the details! We highly recommend that you download the examples (hit right click, and select 'Save Image As...') and do a side by side comparison when you are filling out the documents.

Provide the Letters of Authorization for Sender ID Registration

This Undertaking document authorizes Twilio, Inc. to register and send branded SMS messages on your behalf. 

Once you have downloaded the forms, follow these general instructions: 

  1. Fill in the yellow highlighted fields—completely replace each field with your own information. If a field is not highlighted, don’t change it.
  2. If you have questions on how to fill in the required fields, refer to the annotated examples we provided for each field. 
  3. Have the documents signed by an authorized signatory of the Sender.
  4. In the highlighted fields, add the Sender’s letterhead and/or logo, stamp and sign where indicated.
  5. Upload the forms to the Twilio Alphanumeric Sender ID Registration Form.

Required fields include:

  • Sender Company’s letterhead
  • Alphanumeric Sender ID requested
  • Sample message categories and content
  • Name, signature and position of Authorized Signatory
  • Sender Company stamp







Provide Operators' Masking Templates

Required fields include:

  • Alphanumeric Sender ID requested
  • Company Name
  • Sample message categories and content
  • Terms and Conditions URL
  • Privacy Policy URL
  • Company Website
  • Field of Business

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