If your business sends SMS messages using a sender name — like "MyBrand", "MyBank" or "MyStore" — instead of a phone number, there's a date you can't afford to ignore: June 7, 2026. From that day on, any message sent with an alphanumeric sender ID that isn't registered in Spain's new CNMC Alias Registry will be automatically blocked by mobile operators and will never reach its recipient.
This isn't a future warning: the legal framework is already in force, the deadlines are running, and the registration process has an even earlier internal deadline: April 24, 2026.
In this article we explain exactly what the Alias Registry is, who it affects, what you need to register, and how Instasent manages the process for you.
What is the CNMC Alias Registry?
The Alias Registry is an official database managed by Spain's National Markets and Competition Commission (CNMC) where all alphanumeric sender IDs used to send SMS, MMS and RCS messages to Spanish phone numbers must be registered.
An alias is simply the name that appears in the sender field of a text message. Everyday examples: BBVA, CORREOS, MYBRAND. Until now, any company could use virtually any name. From June 7, 2026, only properly registered aliases linked to an authorised provider will be allowed.
Why did the CNMC create this registry?
The regulation is a response to the rise of smishing fraud: SMS messages that impersonate banks, public institutions or well-known brands to trick users into handing over personal or banking data. The solution is to require that every alias corresponds to a real, identified and verified company.
The Alias Registry is based on two pieces of legislation:
- Ministerial Order TDF/149/2025, which established the registration obligation and blocking requirements for operators.
- CNMC Circular 1/2026, published in the Official State Gazette (BOE) on March 27, 2026, which sets out the procedure, deadlines and technical requirements for the registry.
Who does this regulation affect?
The regulation applies to any company or public body that uses an alphanumeric sender ID to send messages to Spanish phone numbers, regardless of where the messages originate:
- Spanish companies sending transactional SMS, OTPs, alerts, notifications or marketing campaigns.
- Foreign companies communicating with customers in Spain. Messages sent from abroad with an alias not registered in the Spanish Registry will also be automatically blocked.
- SaaS platforms, CRMs, ERPs and other tools that integrate messaging channels to send messages on behalf of their clients.
Messages with an exclusively numeric sender ID fall outside the scope of this regulation.
Key dates to mark in your calendar
| Date | What happens |
|---|---|
| March 28, 2026 | CNMC Circular 1/2026 enters into force |
| April 24, 2026 Action required | Deadline to provide your data to Instasent and be included in the bulk registration |
| Until June 6, 2026 | Testing period and system adaptation for operators |
| June 7, 2026 Hard deadline | Blocking obligations take effect: unregistered aliases = blocked SMS |
| September 28, 2026 | End of the extended transitional verification period |
April 24 is the critical date for Instasent clients. Before that date, authorised PRO providers can submit a bulk data file to the CNMC covering all aliases currently in use. It's the fastest and most reliable way to guarantee the continuity of your sending.
What happens if you don't register your alias?
The consequence is direct and without exception: your messages will not reach their recipients.
From June 7, 2026, all Spanish mobile operators (Movistar, Vodafone, Orange, MásMóvil, Yoigo, among others) are legally required to automatically block any message whose alphanumeric sender ID does not appear in the CNMC Alias Registry or has not been sent through an authorised provider.
This is especially critical for time-sensitive use cases: OTP authentication, security alerts, transactional notifications or order confirmations. A blocked alias on June 7 gives no warning, no bounce message, no readable error — it simply stops delivering.
Additionally, non-compliance with the regulation may result in significant financial penalties under Spain's General Telecommunications Law.
What you need to register your SMS alias
To register an alias, the CNMC requires proof of a legitimate link between the sender name and the company holding the alias. This can be demonstrated through:
- A registered trademark at the OEPM (Spanish Patent and Trademark Office) or EUIPO.
- A registered trade name at the OEPM.
- A company name registered in the Spanish Commercial Registry.
- An internet domain registered via Red.es or ICANN-accredited registrars.
- A declaration of habitual and legitimate professional use of the alias, if none of the above apply.
Information you will need to provide
Important
Regulations expressly prohibit Instasent from filling in holder or legal representative data on your behalf. This information must come directly from the client company. We handle the technical process with the CNMC — you provide the information.
To complete the form, log in to your Instasent dashboard at Settings > Organization > Legal Profile, or check our step-by-step guide in the Help Center.
What are the alias format rules?
| Allowed | Not allowed |
|---|---|
| ✓Between 3 and 11 characters | ✗Numbers-only aliases |
| ✓Letters a-z, A-Z (including ñ and ç) | ✗Accented characters (á, é, í...) |
| ✓Digits 0–9 | ✗Special chars: ! ? # % * € () [] |
| ✓Special chars: @ & - _ . + | ✗Generic names: "Bank", "Message", "Urgent" |
How Instasent handles the registration for you
Instasent acts as an authorised Origin Provider (PRO) before the CNMC. We are the technical provider enabled to originate messages using your alias and can manage the registration on your behalf.
You complete the form with your company details and aliases from your Instasent dashboard.
We prepare the official file in the format required by the CNMC.
We submit it through the bulk registration process before April 24.
The CNMC processes the request and may contact the legal representative you indicated to verify the link.
Your alias is registered and your sending continues without interruption.
The CNMC's validation period is up to one month under normal conditions and up to three months during the transitional period ending September 28, 2026.
Frequently asked questions about SMS alias registration
All alphanumeric sender IDs you use to send messages to Spanish phone numbers must be registered. If you use several different senders — by brand, service or campaign — each one must be registered separately.
Yes. You can file the registration directly through the CNMC's electronic office. However, you will need a digital certificate and the alias must be linked to an authorised PRO provider like Instasent for messages to be sent through it.
Yes, in terms of the registration obligation. It only applies to messages sent to Spanish phone numbers. However, foreign companies that send messages to customers in Spain are also required to register their aliases.
In that case you act as a "third party" under the regulation. You will need to manage the registration of each alias linked to its actual holder, ensuring each client provides the necessary authorisation. The CNMC will notify the holder to confirm registration within 10 working days.
The CNMC may reject an alias if it fails to demonstrate a legitimate link, could cause confusion with other brands, or does not comply with formatting rules. In that case you will need to submit a new application with an alternative alias.
Official sources: CNMC Circular 1/2026 (BOE) · Ministerial Order TDF/149/2025
Time is running out: April 24 is the deadline to provide your data to Instasent and be included in the CNMC bulk registration. If you use SMS with an alphanumeric sender and don't act before June 7, your messages will be automatically blocked. Complete the form from your dashboard at Settings > Organization > Legal Profile, or check our step-by-step guide in the Help Center. Any questions? Contact us with the subject "CNMC Registration".
