Spain alphanumeric sender ID (alias) registration guidelines

Use this page to understand the sender registration requirements for Spain and register your alphanumeric sender IDs (aliases) in compliance with Spanish regulations.

The National Markets and Competition Commission (CNMC) of Spain has introduced a mandatory Alias Registry (Registro de Alias) under Order TDF/149/2025. All companies, both Spanish and international, that send SMS or RCS messages to Spanish phone numbers using alphanumeric sender IDs must pre-register those aliases in the CNMC Alias Registry.

From September 15, 2026, Spanish mobile operators are legally required to block any SMS/MMS/RCS message that uses an alias not listed in the registry. Unregistered traffic will not be delivered.

Who does this affect?

This requirement applies to you if:

• You send SMS or RCS messages to recipients in Spain, and
• You use an alphanumeric sender ID (alias), for example, a brand name or company name as the sender.

Alias requirements

Your alias must meet the following rules to be eligible for registration:

Registration process

Key actors

You can register your aliases using one of the following options:

What you need to register [#what-you-need-to-register-registration-process]

The legal representative of the sender-owner must have a valid digital certificate to access the CNMC portal. Use the portal to submit senders for registration, edit sender details, and approve requests raised by a third party or PRO. The legal representative has 10 days to approve requests raised by third parties or PROs before the regulator processes them. The CNMC provides a list of trusted certificate providers in Spain.

If the alias-holder does not have a valid digital certificate, it can authorize an external representative who has one to access the CNMC portal. To authorize an external representative (for example, Infobip), complete and sign an authorization letter. Complete the Spanish (right) side of the letter. The English translation is provided for reference.

It is also acceptable to complete and sign both sides, but the Spanish side is mandatory. The signature can be handwritten or electronic, as long as it is valid under the laws of the sender-owner home country. Infobip can then act as your representative on the CNMC Alias Registry portal. As your representative, Infobip can change sender details, receive notifications from CNMC, and submit sender registration requests without requiring approval from the sender-owner.

Non-Spanish clients can also obtain an eIDAS certificate (European digital certificate). A company digital certificate can also be issued, which allows company employees to access the portal.

Have the following sender information ready before you start:

Alias-holder/sender-owner details:

• Tax ID Number of the company or public administration that wishes to own the alias
• Name of the company or public administration that wishes to own the alias

Legal representative of the sender/alias owner details (the representative needs to have a valid digital certificate to access the CNMC portal; regulator recognizes two types of sender-owner representatives: Natural Person or Legal Entity):

Natural Person details:

• Name of the natural person representative
• Tax ID of natural person representative
• First Surname of the natural person representative
• Second Surname of the natural person representative (optional)
• Emails, separated by semicolons
• Telephone Number(s), separated by semicolons (optional)

Legal Entity details:

• Company Name
• Tax ID Number of the legal entity representative. Spanish companies: provide the NIF. EU companies: provide the EU VAT ID. Companies outside the EU: provide the EU VAT ID if possible. CNMC may not accept a tax ID that is not an NIF or EU VAT ID.
• First Name of the natural person representative of the Legal Entity
• Tax ID Number of the natural person representative of the Legal Entity
• Surname of the natural person representative of the Legal Entity
• Second Surname of the natural person representative of the Legal Entity
• Emails for contact, separated by semicolons
• Telephone Number(s) for contact, separated by semicolons (optional)

Alias/Sender details:

• Sender/Alias
• Message Type: can be SMS/MMS/RCS
• Legitimate Linkage: the connection between the requested sender and any of the dropdown options that it matches (RCS sender registration does not require this). One of the following is selected:
  • Registered trademark (OEPM/EUIPO)
  • Trade name (OEPM)
  • Corporate name (Companies Register)
  • Internet domain (Red.es/ICANN)
  • Denominations registered in other national or international public registries
  • Legitimate and habitual use (used when nothing above is applicable)
• Specify the legitimate connection: the registered trademark or trade name or corporate name or internet domain or other registries. If legitimate/habitual use is selected, write explanation

Third Party details (conditional, only if a third party exists): provide the same details as for the legal representative.

Self-registration steps [#self-registration-steps-registration-process]

Download and follow the step-by-step guide:

• Spain self-registration steps

Infobip-assisted registration [#infobip-assisted-registration-registration-process]

Contact Support or your account manager to get help with the registration.

Key dates

What happens if you do not register?

From September 15, 2026, Spanish operators must block:

• Messages sent using aliases not registered in the CNMC Alias Registry
• Messages sent by providers or third parties not designated for a specific alias
• International messages using Spanish-format aliases without valid registration

There is no grace period after the deadline. Unregistered traffic will not be delivered.

Need help?

For questions about this registration or to get assistance with the process, contact Support or your account manager.