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.

Spain's 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 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.

NOTERegistration is free of charge. The CNMC covers all registry costs.

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.

NOTENumeric senders are not affected by this registry.

Alias requirements

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

Rule	SMS aliases	RCS aliases
Length	3 to 11 characters	3 to 40 characters
Allowed characters	Letters a-z, A-Z, ñ, ç; numbers 0-9; special characters: space, @, &, -, _, ., +	Same as SMS
Not allowed	Pure numeric aliases (for example, "123456"), leading or trailing spaces, consecutive spaces, any character not in the allowed set	Same as SMS

Registration process

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

Option	How
Self-registration	Register your alias directly on the CNMC Alias Registry portal using your digital certificate. Designate Infobip as your origin provider during the registration. A third-party partner can also do this on behalf of the alias holder.
Infobip-assisted registration	Contact Support or your account manager. They will guide you through the process and submit the registration on your behalf where applicable.

What you need to register

The legal representative of the company must have a valid digital certificate to access the CNMC portal. CNMC has shared a link (opens in a new tab) to trusted certificate providers in Spain.

The legal representative can also be an authorized external representative company or person that has a valid digital certificate to access the CNMC portal. In order to authorize an external representative (for example, Infobip), you will need to fill in and sign an authorization letter that will soon be uploaded here once CNMC provides the required format of the template.

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 information ready before you start:

Alias/sender ID details: requested alias or aliases, associated brand name, official web domain, primary link of the alias, type of SMS/RCS use, expected activation date, and end date
Alias holder (company) details: company legal name, tax ID (Spain or intra-community VAT), registered address, and country
Legal representative details: full name, national ID/NIE/passport, email address, and mobile phone number
Originating provider and authorizations: originating provider (PRO), declaration of ownership, authorization for alias registration and management, and operational routing authorization
Justification of alias ownership: explanation of the legitimate link between the alias and the brand, entity, domain, or corporate name
Third-party usage confirmation: indication of whether any authorized third party is involved in the management, use, or exploitation of the alias
Authorized third-party details (if applicable): legal name, tax ID or VAT number, registered address, legal representative's name, email, phone number, and role in relation to the sender ID

Self-registration steps

Download and follow the step-by-step guide:

Spain self-registration steps (opens in a new tab)

NOTEIf your messaging provider (PRO) is not registered as a Provider in the CNMC portal, they will not appear in the portal provider list and can only be designated as a third party. Confirm your provider's status before submitting.

Infobip-assisted registration

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

Key dates

Date	Event
March 28, 2026 - September 14, 2026	Testing environment available: register and validate your aliases
September 15, 2026	Blocking enforcement begins: unregistered aliases will be blocked by Spanish operators

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.