> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://helpdesk.closum.com/sitemap.xml
> Use this file to discover available pages before exploring further.
> Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash).

# Spain

### Overview
Starting **June 7, 2026**, all alphanumeric Sender IDs (aliases) must be **pre-registered** in the official registry managed by the CNMC, and their use must be authorized through a registered provider such as **Closum**.

**To register your Sender ID, please complete the [form via this link](https://datahub.closum.com/dashboard/#/nc/form/098137e9-1a37-4603-b8c6-bf694d236fa0/survey).**

This regulation applies to **SMS, MMS, and RCS** messages.
The main goal of this regulation is to reduce fraud related to message identity, preventing impersonation and misuse of Sender IDs.

👉 If a Sender ID is not registered by this date, messages sent using that alias will be **blocked** and **not delivered**.


### Sender ID (Alias) and Format Requirements
A **Sender ID (alias)** is the alphanumeric name (for example, a brand name) that appears to recipients instead of a phone number.

#### SMS/MMS
| Rule | Requirement |
| ---- |
| Length | Minimum 3 characters, maximum 11 |
| Allowed characters | Letters (a–z, A–Z including ñ, ç) · Numbers (0–9) · Spaces (not consecutive, not at start/end) · Special: @ & - _ . + |
| Not allowed | Numeric-only · Generic names (e.g., "Message", "Bank", "Flight", "Urgent", "INFO", "SMS") · Offensive language · Impersonation · Consecutive spaces · Accented characters (á, é, í, ó, ú) · Symbols: ¡ ! # % ( ) * , / : ; < > = ? [ ] € |
| Case sensitive | Yes |

#### RCS
| Rule | Requirement |
| ---- |
| Length | Minimum 3 characters, maximum 40 |
| Connection | Must clearly relate to a registered trademark, trade name, company name, or domain |
| Not allowed | Same restrictions as SMS/MMS |
| Case sensitive | Yes |



### Registration Process
Registration is submitted through the CNMC electronic portal and requires authentication with a valid Spanish digital certificate.
Two main parties are involved:
* **Alias Holder** — the company using the Sender ID, which must demonstrate a legitimate connection
* **Closum (Authorized Provider)** — the platform responsible for delivering SMS and RCS messages in Spain
Registration can be submitted:
* Directly by the alias holder
* Or by Closum on behalf of the customer
👉 If Closum manages the registration, the CNMC will contact the holder to confirm authorization.
After registration:
* Traffic will only be allowed through the authorized provider
* Non-registered Sender IDs will be blocked

### Phase 1 (April 2026)
Submit the registration request (via CNMC portal or with support from Closum).
For bulk submissions, required information should be provided by **April 20, 2026**.
Single submissions after this date should be made via the CNMC portal or through Closum.

### Information Required for Registration
| Field | Details | Required |
| ---- |
| Sender ID / Alias | 3–11 chars (SMS/MMS) or 3–40 chars (RCS) | ✅ |
| Type of connection | Relationship to the brand (trademark, domain, etc.) | ✅ |
| Provider | Closum | ✅ |
| Holder type | Individual or Company | ✅ |
| Tax ID | NIF/NIE/Passport or CIF/NIF | ✅ |
| Holder name | Individual or legal company name | ✅ |
| Representative details | Name, tax ID, email, phone | ✅ |
| Activation date | DD/MM/YYYY | Optional |
| End date | Max 24 months | Optional |

### Phase 2 (May 2026)
After submission, the alias holder will be contacted by the CNMC to:
* Access the portal using a digital certificate
* Submit proof of ownership/connection
* Confirm Closum as the authorized provider
⏱️ Timelines:
* Up to 10 business days to respond
* Approval timeframe:
    * ~1 month (standard)
    * Up to 3 months (initial phase until September 2026)
If corrections are required:
* A 10-day window is granted
* Failure to respond may result in the application being cancelled

### Important Requirements to Complete Phase 2

#### Spanish digital certificate
A valid Spanish digital certificate is required (e.g., FNMT).
If not available:
* An EU-based authorized representative must be appointed

#### Proof of ownership
The CNMC will require proof of a legitimate connection to the alias.
Examples include:
* Registered trademark (OEPM or EUIPO)
* Registered trade name
* Legal company name
* Internet domain
* Public registries
If none apply:
* A professional use declaration supported by documentation may be used

### Sender ID (Alias) Lifecycle and Maintenance
* **Maximum validity:** 24 months
* **Auto-suspension:** after 12 months of inactivity
* **Reactivation window:** 1 month
* **Permanent cancellation:** after that period
* **Re-registration:** only possible after 6 months

### Need Help?
If you have questions or need assistance, please contact your Account Manager or reach out to the **Closum** support team.