Overview
From June 7, 2026, any alphanumeric Sender ID (also known as an alias) must be registered in advance with the official Alias Registry operated by the CNMC (CNMC, Spain's National Commission for Markets and Competition). Use of these Alpha Tags must also be approved through an authorized messaging provider such as Sinch ClickSend.
If a Alpha Tag has not been registered by this deadline, messages sent using that alias will be blocked and will not reach recipients.
Registration Process
Applications will be submitted to CNMS by Sinch ClickSend and will require authentication using a valid Spanish digital certificate belonging to the applicant or an authorized representative.
There are two key participants in this process:
The Alias Holder — the company that uses the Sender ID and must be able to demonstrate a legitimate connection to it (check the Proof of ownership section below).
Sinch ClickSend — the messaging provider that delivers the SMS and RCS messages to Spain.
Step 1
Start the process by submitting a registration request through ClickSend. This involves completing the required form:
https://clicksend.jotform.com/261091120619045
Step 2
After submission, the Alias Holder will be contacted by the regulator to verify ownership through the CNMC portal.
You will need to:
Sign in to the CNMC portal using your digital certificate
Upload your proof-of-ownership document — Confirmation of the connection type and business purpose of the Sender ID will be requested directly by CNMC. CNMC notifies the alias holder to confirm the connection to the alias and the relationship with Vonage (within 10 business days of notification)
Confirm Sinch as your registered provider — CNMC will send you a notification; you must approve this within 10 business days by logging into the CNMC portal.
CNMC reviews and validates the submission — up to 1 month normally; up to 3 months during the first 6 months after the Circular enters force (i.e., until September 2026)
Alias is registered and authorized for use
*If the CNMC requires corrections, a 10-day window is granted to provide them; failure to respond may result in the application lapsing
Once approved, the Sender ID will be officially registered and permitted for use with ClickSend.
Important Requirements to complete registration
Spanish digital certificate
Your authorized representative will need a valid FNMT-RCM digital certificate to access the CNMC portal. This requires a Spanish DNI, NIE, or EU registration certificate. Non-EU and non Spanish NIE representatives cannot obtain this certificate directly and should consult their legal advisor about appointing an EU-based authorized representative.
Proof of ownership
The CNMC will request proof of Legitimate connection. In simple terms, it means being able to demonstrate that the alias has a direct and reasonable link to the organization requesting it.
This is typically evidenced through verifiable elements such as:
Registered trademark with OEPM (Spanish Patent and Trademark Office) or EUIPO
Registered trade name with OEPM
Corporate legal name registered in the Commercial Registry
Internet domain registered with Red.es or ICANN-accredited registrars
Other public registries (national or international)
Professional use declaration (if none of the above apply — requires a sworn statement plus authenticated contracts or supporting documentation)
The CNMC requires a responsible declaration justifying the connection, but organizations should have supporting documents available in case the CNMC requests additional information.
FAQ's
How long is my Alpha Tag (alias) valid for?
Your registered Alpha Tag will be valid for a maximum of 24 months, however this will be automatically suspended after 12 months if not used.
What happens if my Alpha Tag (alias) expires or is suspended?
The alias holder has 1 month to reactivate a suspended alias; otherwise, it is permanently cancelled and will need to go through the registration process again. There is a 6-month cooling-off period before you will be able to register.
Why is the Spanish Regulator enforcing this?
The regulation's primary goal is to minimize fraud associated with message identity. By controlling and registering these aliases, the CNMC aims to prevent their misuse for impersonation, confusion, or fraudulent activities.