The Spanish National Markets and Competition Commission (CNMC) requires every alphanumeric Sender ID used to send SMS messages to Spanish mobile numbers to complete registration in the CNMC Alias Registry (Registro de Alias). Starting September 15, 2026, operators block unregistered Sender IDs and the messages cannot be delivered. This notice describes the background of the regulation, the registration process, and the required materials, to help you complete compliance registration before the deadline.
CNMC mandatory alias registration policy
The Spanish National Markets and Competition Commission (CNMC) 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 their aliases in the CNMC Alias Registry.
From September 15, 2026, Spanish mobile operators are legally required to block any SMS, MMS, or RCS message that uses an alias not listed in the registry. Unregistered traffic will not be delivered.
Purely numeric Sender IDs are not subject to this regulation.
Scope of impact
If you use alphanumeric Sender IDs to send SMS or RCS messages to Spanish mobile users through Alibaba Cloud Short Message Service, and you have not completed CNMC Alias Registry registration, the following impacts apply starting September 15, 2026:
Messages sent with an unregistered alias will be blocked by Spanish mobile network operators (MNOs), mobile virtual network operators (MVNOs), and messaging aggregators.
Unregistered traffic will not be delivered to end users, affecting normal business operations.
Key dates
Date | Description |
September 15, 2026 | The enforcement date set by the draft from Spain's Ministry for Digital Transformation. On that date, Spanish operators start blocking messages that use an unregistered alias. Make sure you complete registration before this date. |
Because the registration process involves review by CNMC, submit your registration as early as possible to allow enough time for approval.
Who needs to register
The following parties can submit alias registration to CNMC:
Alias owner: The company or public administration that owns the Sender ID.
Authorized third party (TERCERO): A third party authorized by the alias owner to handle the registration on their behalf.
Originating Provider: An originating provider registered with CNMC, submitting the registration on behalf of the alias owner.
If a third party submits the registration, the record will be placed in "pending authorization" status. The alias owner must confirm or reject the registration within 10 days of receiving the CNMC notification. Failure to respond within this period is treated as an incomplete registration.
Required registration materials
Prepare the following materials as required by CNMC alias registration:
Company information
Full legal company name
NIF/CIF (Spanish tax identification number) or EU VAT number
Registered company address
Legal representative information
Full name
NIF (tax identification number) or passport number
Mobile phone number
Email address (for receiving registration-related notifications)
Information required for each alias
Alias name: The alphanumeric Sender ID.
Description of use case: Describes the specific purpose of the alias.
Activation date: Regardless of the date you specify, the alias cannot be used before the registration completion date.
Expiry date: Must not exceed 24 months from the registration date.
Registration process
You must complete the registration yourself using a digital certificate (certificado electrónico) by logging in to the CNMC Alias Registry Portal.
Login requirement: Access to the CNMC Electronic Office requires authentication through Cl@ve or a recognized electronic certificate. The certificate must be valid on the Spanish Public Administration @firma platform and must be held by the authorized legal representative. If you do not yet have an electronic certificate, refer to the "requisitos técnicos" section on the CNMC Electronic Office page for instructions.
Registration steps:
Access the portal and log in. Open the CNMC Alias Registry Portal and navigate to the Gestión del Registro de alias page. If you hold a Spanish electronic certificate, select Acceso con certificado electrónico. If you are using an EU member state eID, select Acceso desde Cl@ve, then select your country and identity provider.
Fill in the applicant (Solicitante) information. Select your applicant identity:
En nombre propio (applying in your own name): Enter your personal NIF, last name, and first name.
En representación de (applying on behalf of a company): Enter the company NIF and company name.
The email address (correo electrónico) is mandatory and is used to receive CNMC notifications. A phone number is optional.
Select the request type (Tipo de solicitud):
Inscripción de Alias: First-time alias registration submission.
Autorización de alias: Used by the alias owner to confirm authorization for a registration submitted by a third party on their behalf.
Add the legal representative (Representante del titular) of the alias owner. Select "Natural person (Persona física)" or "Legal entity (Persona jurídica)" and fill in the representative's NIF, name, and company name (if applicable). Check Recibir notificaciones and enter at least one email address to receive CNMC notifications.
NoteThe representative must hold an electronic certificate that allows login to the CNMC Electronic Office. CNMC will subsequently send authorization confirmation requests via the account associated with that certificate.
Add aliases (Añadir alias) and fill in the details. You can add multiple aliases in a single submission. For each alias, provide the following:
Alias name: The alphanumeric Sender ID.
Description of use case: A clear, specific, and identifiable purpose, with a unique correspondence to the alias owner.
Activation date: Regardless of the date you specify, the alias cannot be used before the registration completion date.
Expiry date: Must not exceed 24 months from the registration date.
Proof of legitimacy (choose one of six options): CNMC requires you to select one type of legitimacy basis for each alias and provide the corresponding proof:
A trademark registered with the Spanish Patent and Trademark Office (OEPM) or the European Union Intellectual Property Office (EUIPO).
A trade name registered with the Spanish Patent and Trademark Office (OEPM).
A company name legally registered with the Spanish Commercial Registry (Registro Mercantil).
An internet domain name registered with Red.es or ICANN.
A name registered with another national or international public registry (applicable to entities outside Spain).
Legitimate and customary professional use (fallback option when none of the above five apply; a detailed justification is required).
Associate a messaging service provider (Provider) with each alias. Select the service providers recommended to you during Alibaba Cloud registration.
ImportantSelect all providers recommended by Alibaba Cloud. You bear any delivery failures and losses caused by not selecting all recommended providers.
Select the message channel. Indicate whether the alias is to be used for SMS, RCS, or both. If you apply for both SMS and RCS, CNMC will issue two separate authorization requests, which must each be confirmed independently.
Review and submit. Select all the terms check boxes, then click Revisar y Presentar to preview your application. Once confirmed, click PRESENTAR to formally submit. To make changes, click VOLVER. After submission, wait for CNMC review. If the registration was submitted by a third party, the alias owner must log in to the portal using their own electronic certificate within 10 days to complete Autorización de alias authorization confirmation.
Alias (Sender ID) naming rules
CNMC has specific format requirements for registerable aliases. Applications that do not meet these requirements will be rejected:
Length must be between 3 and 11 characters.
By default, only letters a–z, A–Z, digits 0–9, and spaces are accepted. If other characters are needed, you must include a justification in your application.
Characters with accent marks are not accepted.
Consecutive spaces are not allowed. Spaces at the beginning or end of an alias are not allowed.
Purely numeric aliases are not allowed.
Generic words that do not reflect the sender's identity or could cause confusion are not allowed, for example: message, Bank, Flight, Urgent.
Proper nouns (personal names, geographic names) and offensive terms are not allowed.
If CNMC determines that an alias could cause confusion, facilitate fraudulent misuse, or contains offensive content, it reserves the right to reject the application. A single owner may register multiple aliases, provided each alias has a clearly identifiable purpose and a clear correspondence with the owner.
FAQ
What is an Alias under CNMC regulation?
An Alias is an alphanumeric Sender ID. This regulation does not apply to purely numeric numbers or short codes that fall within national or international telephone numbering plans.
Who can submit alias registration?
There are three types of eligible parties: the alias owner (a company or public administration), an authorized third party delegated by the owner, and an originating provider registered with CNMC submitting on behalf of the owner.
How many aliases can a single owner register?
CNMC does not set an upper limit on the number of aliases, provided that each alias complies with the format rules and has a clear correspondence with the owner.
Can I register multiple aliases in a single submission?
Yes. Multiple aliases belonging to the same owner can be submitted in a single application. However, each alias must have its own complete form filled out separately.
What happens if I fail to register by the deadline?
From the effective date of the CNMC alias registration policy (as of the time of writing, the latest proposed date is September 15, 2026, subject to the official gazette), messages sent with an unregistered alias will be blocked outright by Spanish mobile operators and will not be delivered to end users.
Do purely numeric Sender IDs need to be registered?
No. This CNMC alias registration policy applies only to alphanumeric Sender IDs. Purely numeric Sender IDs are not affected.
How do I manage my Sender IDs on Alibaba Cloud?
You can manage your Sender IDs through the Register a sender ID feature in the Alibaba Cloud Short Message Service console.