How to Know if an SMS Is Certified: Detailed and Practical Guide

What Is a Certified SMS?

A certified SMS is, basically, a standard text message sent to the recipient’s mobile phone, but accompanied by a digital certification process. Unlike a standard SMS, this service uses advanced technologies (electronic signature, timestamps, blockchain, etc.) to ensure the authenticity, integrity, and delivery of the message.

If you’re wondering what a certified SMS is, the answer is simple: it’s a legally valid SMS that acts as an official notification. In practice, it works like a digital burofax or registered letter. The recipient receives the message on their phone, while the system simultaneously generates an electronic certificate (e.g., a PDF) that records the exact date, time, and content of both the sending and delivery.

Example: a clinic sends a certified SMS to a patient to notify a change in their appointment. The patient receives the message in seconds, and the clinic obtains a certificate with the time, date, and message content.

Thus, a certified SMS not only transmits information efficiently but also leaves an unalterable record of the notification—just like traditional registered mail or a burofax. In summary, a certified SMS is an SMS with legal value that serves as an official notification method, validated by trusted entities.

Characteristics of a Certified SMS

To fully understand what a certified SMS is, it’s important to analyze its technical and legal elements. A certified SMS integrates several components and processes that give it its unique properties. It requires a specialized infrastructure: a mobile network operator, a sending platform or API, and a qualified trust service provider responsible for certifying the message.

The final message contains several formal components: header, body, metadata, and typically an associated digital proof.

Below, we detail these elements and explain how the certification process works:

Elements That Make Up a Certified SMS

• Message header: Contains basic information about the sending process. The sender—often a verified alphanumeric name instead of a number—and the recipient’s phone number with the date and time of sending. This initial block makes it easy to identify who sent the SMS and when.
• Message content: The text you want to notify. Although it’s usually short, some platforms allow concatenated messages of several hundred or even thousands of characters, depending on the encoding used (GSM7 or UNICODE). This content may include formal information about the subject matter. In a certified SMS, unlike a normal one, this text has evidential value since it’s recorded in the digital certificate.
• Metadata and timestamps: Include technical data about the sending and delivery process: unique message ID, delivery status (sent, delivered, read), and other important events. They also include a digital timestamp that certifies the exact time of each event. These metadata ensure record integrity, enabling traceability and verification.
• Associated certificate or receipt: Once the SMS is delivered, the platform generates an electronic document—typically a signed PDF—containing all the above elements. This certificate includes the message text, sender and recipient data, and timestamps for sending and delivery. It serves as official proof that the message was sent and received and is stored for future reference.

Certification Process: How Authenticity and Delivery Are Ensured

Each certified SMS goes through a special certification process in the platform’s backend before and after being sent. First, the sender submits their SMS through a secure platform or API provided by the service. There, the exact sending time is recorded, and a unique identifier is assigned to the message.

Then, the message is passed to the mobile operator, which sends it to the recipient’s phone. This entire process (sending to the operator, delivery to the phone, and sometimes message opening) is digitally logged. Technologies like digital signatures and blockchain play a key role.

The digital signature authenticates the sender’s identity, preventing impersonation, while blockchain or timestamps ensure that no steps can be modified retroactively. In practice, this means that if someone tried to alter the message or timestamps after sending, the digital records would expose it.

Thanks to this process, the content, date, and sender are guaranteed, transforming the SMS into a legally binding notification.

Sending and Delivery Log: How the Process Is Documented

One of the most useful features of certified SMS is its complete traceability. Once the message has been sent and received, the sending platform provides the sender with an official delivery receipt and the corresponding digital certificate.

This proof, usually an electronic PDF, includes all details: sending and delivery dates and times, message content, sender and recipient data, and more. This ensures total traceability.

The sender can always prove what was sent and when, which is crucial in case of disputes. The records are stored indefinitely and serve as irrefutable evidence since they are digitally signed documents.

How to Identify a Certified SMS

At first glance, it’s not always obvious how to know if an SMS is certified—it may look like a regular message. However, there are some clues and actions that can help confirm whether it truly is certified. Below are the most common ways to know if an SMS is certified.

Visual or Textual Indicators in the Message

There’s no mandatory standard format, but many certified SMS messages include small indicators in the message body. Some providers add introductory texts such as “Official notification,” “Certified SMS,” or a reference code at the beginning.

Others use identical wording to a standard SMS without explicit notice. In such cases, you should check the sender: if the message comes from a commercial (alphanumeric) name instead of a generic number, it indicates a certified system. One simple way to identify a certified SMS is to look at the sender’s name.

For example, if you receive an SMS from “BankXYZ” that includes a transaction code and a link to verify the certificate, it’s a clear sign that it’s a certified SMS.

In practice, it’s best to read the SMS carefully: formal language, references to legal matters, or links to certificates can be signs that it’s a certified SMS. Another useful clue is the presence of a link to the certificate or a verification code.

However, certified SMS often look identical to regular ones on your phone screen; that’s why you should pay attention to both the sender and the indicators described below.

These indicators are essential if you want to quickly learn how to tell if an SMS is certified.

Sender Information: How to Verify Authenticity

A key factor is who sent the SMS. Certified SMS services require that the sender be previously registered and authorized on the platform. This means the SMS usually comes with a validated identifier. For example, the sender name may appear as the company’s official name instead of a phone number.

If the sender is an official name (and matches the expected company), that’s an indication that the message was sent through a certified channel. Also, since the sending is digitally signed, it guarantees that the message truly originates from the stated source.

If you have doubts about the sender, it’s recommended to contact the company directly (for example, through their legal or customer service department) to confirm the authenticity of the received SMS. An unverified or unknown sender should be treated with caution.

Therefore, one of the most reliable ways to tell if an SMS is certified is to confirm that the sender is verified.

Verification via Third-Party Platforms or Services

The most secure way to confirm is through the certifying platform itself. Many certified SMS providers offer a web portal where you can check the generated certificates. This allows both the sender and, in some cases, the recipient to verify the SMS.

In some systems, the recipient can enter a message code or reference on a web page to confirm the validity of the associated certificate. In practice, if you’re asking “how to know if an SMS is certified,” the answer is: check the digital certificate. Ask the sender for the PDF or certificate number, or verify it directly with the service provider.

This evidence will confirm that a certified SMS was indeed sent with your data and timestamps, giving you complete certainty and preventing fraud or confusion.

Advantages of Using Certified SMS

If you’re still wondering how to know if an SMS is certified, these advantages will convince you why more and more companies are using it. Certified SMS combines the immediacy of traditional text messaging with enhanced legal guarantees.

Its main benefits include:

Legal Security: Validity in Case of Disputes

A certified SMS has full legal validity, comparable to that of a burofax or registered letter. In Spain, for example, it is recognized in court as reliable evidence of sending and delivery.

Likewise, in the European Union (under the eIDAS regulation) and in several Latin American countries, it’s considered a legally valid notification, admissible as evidence in audits and disputes. In Latin America, although regulations vary by country, more legal frameworks are recognizing certified SMS as official notification.

This gives businesses legal confidence that any contract change, formal notice, or other notification sent via certified SMS will be admissible as evidence.

In short, communications are backed by digitally signed documents, reducing disputes and ensuring legal certainty.

Speed and Communication Efficiency

Leveraging mobile network coverage, certified SMS messages reach any phone instantly—without relying on the internet. This means delivery in seconds, with no queues or travel required. Since recipients don’t need special apps, critical processes (cancellations, urgent confirmations, legal alerts, etc.) are streamlined and globally accessible.

Moreover, platforms often allow mass or API-based sends, automating notifications and saving operational time. In essence, they combine the immediacy of SMS with more efficient, less bureaucratic processes.

Cost Savings Compared to Other Notification Methods

In terms of cost, certified SMS is much cheaper than traditional methods. By eliminating paper, envelopes, and postal fees, it drastically cuts logistics expenses.

Additionally, integrating it via API automates tasks, saving staff resources. This saving adds to the environmental benefit of going paperless. In summary, companies can optimize their communication budgets for official notifications without losing any legal guarantees.

Example: an insurance company replaces registered letters with certified SMS to notify renewals. Costs drop by 70%, and customers receive the notice within seconds.

How to Send a Certified SMS

Before learning how to send one, it’s important to clearly understand what a certified SMS is and its legal implications. To send certified SMS, you need to hire a specialized provider that complies with current legislation.

In Spain and Latin America, there are several leading services. These providers operate as Qualified Trust Service Providers (QTSP), ensuring compliance with legal frameworks (like eIDAS in Europe). They typically offer web platforms and API interfaces you can use directly or integrate into your existing systems. Below we explain the basic steps to configure and send a certified SMS:

Platforms and Services for Sending Certified SMS

There are various platforms on the market that make it easy to send certified SMS messages with full legal guarantees. These solutions are designed for both companies and professionals who need to communicate sensitive information or official notifications with legal backing.

Among these options, we at LabsMobile offer a specialized service for sending certified SMS with full legal validity, compliant with eIDAS and local notification laws. By choosing us as your provider, you ensure your SMS messages have legal backing as a QTSP (Qualified Trust Service Provider).

With these services, you can send messages quickly, securely, and with the assurance that every communication is supported by a digital certificate.

Steps to Configure and Send a Certified SMS

The steps vary depending on the provider, but they generally follow this structure:

1. Account setup and verification: Register on the provider’s platform and validate your company’s identity. You may be asked for legal documents and to configure your certified alphanumeric sender name.
2. Add recipients: Enter the recipient’s phone number (and optional details like their name). Make sure all data are correct to avoid delivery errors.
3. Write the SMS: Compose your message. Remember there’s usually a character limit (though some systems allow up to 612). Some platforms allow you to attach files or links for more information.
4. Send and confirm: Review everything carefully and send the message. The platform will process and digitally certify it. Within seconds, the SMS will arrive at the recipient’s phone like a normal text.
5. Obtain the certificate: Once the SMS is delivered, the provider generates an official delivery receipt. You can download the certificate (e.g., a signed PDF) containing all relevant information (dates, sender, recipient, content). Save this document—it’s your legal proof of sending. This certificate is the definitive way to confirm a certified SMS.

Legal and Technical Considerations When Using This Service

Before starting, keep several key requirements in mind:

• Certified provider: The service must be a recognized QTSP, for example under eIDAS in Europe. This ensures that the issued SMS messages have legal backing (official timestamps, certificate custody, etc.).
• Approved sender: Many providers require you to register and pre-approve your sender (alphanumeric name). This prevents your SMS messages from being marked as spam and ensures sender transparency.
• Length and format: Although certified SMS often support more characters, it’s best to keep messages concise. Avoid using emojis or special characters that could alter text encoding.
• Legal compliance: The content must comply with data and messaging laws—for example, don’t send confidential information without consent or prohibited content. Always respect recipient privacy and avoid spam practices.
• Technical integration: If you use an API, make sure to use secure channels (HTTPS) and handle errors properly—for example, how to react if a send fails.
• Certificate storage: Plan how you’ll store downloaded certificates. By law, you usually need to keep them for several years. Many providers store them in the cloud, but it’s also recommended to download and archive the PDFs of your certified SMS.

By following these guidelines, you’ll ensure that every message you send is truly a certified SMS with full guarantees.

Now that you know what a certified SMS is and how to send one, you can start using it in your business with legal security. If you want to learn more about implementing a certified SMS service in your company, don’t hesitate to contact the LabsMobile team. Our experts will help you configure sending, verify delivery, and make the most of the legal and operational advantages of certified SMS.

Register for free and send your first certified SMS from our platform.