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Alphanumeric Sender ID for Twilio Programmable SMS

In addition to the wide use of SMS messaging for personal conversations (person-to-person, or P2P messaging), messaging by businesses (application-to-person, or A2P messaging) is exploding as one of the most widely used channels for business communication with customers. Common use cases include marketing, mass alerts, verifications, and notifications.

Article contents:

What is an Alphanumeric Sender ID?

Alphanumeric Sender ID allows you to send Twilio Programmable SMS messages to supported countries from a personalized sender ID (like a business or organization name), instead of your E.164 formatted Twilio Phone number.

The example below shows how an Alphanumeric Sender ID (AUTHMSG) would look in place of the standard number. 


Benefits of messaging with Alphanumeric Sender ID

Higher message deliverability: In many countries, regulatory bodies are increasingly filtering illegitimate A2P SMS use cases to curb unwanted messaging. For every Alphanumeric Sender ID request, Twilio completes a rigorous due-diligence and registration process with the telecommunication carrier in that country. Once this process is completed, Twilio handles fluctuating telecom logic, regulations, and carrier-specific rules to ensure your A2P messages reach their destination.
Improved brand recognition: Because recipients see your name with every SMS sent, using a recognizable Alphanumeric Sender ID reinforces your branding.
Increased open rates: As cases of spam and fraud increase, being able to easily identify the sender is a key factor in whether recipients decide whether to open a message. If the sender is an international or unfamiliar number, the chance of the message being opened is next to none. With Alphanumeric Sender IDs, recipients immediately recognize the sender and know the message is legitimate. As a result, they are up to 80% more likely to open the message.
Alternative to 10DLC A2P messaging

Alphanumeric Sender IDs can help work around the common challenges to A2P messaging as a high throughput and low carrier filtering option. Please note, Alphanumeric Sender ID is not available in the US or Canada.

  • In most supported countries, customers can instantly provision an Alphanumeric Sender ID. These Alphanumeric Sender IDs are known as “dynamic.”
  • Some countries require pre-registration, which means the customer has to provide information and sometimes additional documents, resulting in additional time before the Alphanumeric Sender ID can be used. These Alphanumeric Sender IDs are known as “pre-registered.”

Which Countries Support Alphanumeric Sender IDs?

You can find out which countries support Alphanumeric Sender IDs on this page. The image below shows the first countries (listed alphabetically) in this list, which shows supported countries and provides access to the pre-registration form for those of the countries for which pre-registration is required.


As you can see, the right column shows whether Alphanumeric Sender IDs are supported and whether pre-registration is required. If so, clicking the link in the right column will take you to the form that leads you through the pre-registration process. The link in the left column takes you to the SMS Guidelines.


For customers who have purchased an SMS-capable number, there is no additional charge for using an Alphanumeric Sender ID for most countries. However, for some countries that require pre-registration there may be additional charges, such as one-time setup fees or recurring monthly fees. If so, that information is displayed in the Sender ID registration form of the relevant country. 

Limitations of Alphanumeric Sender IDs

  • Alphanumeric Sender IDs are only supported for paid Twilio accounts; not for free trial accounts.
  • Alphanumeric Sender IDs are not supported in some countries and some supported countries require pre-registration.  
  • Alphanumeric Sender IDs are only available for one-way outbound messages; recipients cannot reply directly to messages. (However, you can provide contact information in your message if you want recipients to respond).  
  • Some use cases are generally prohibited (e.g., gambling, dating sites, adult content, spam, phishing, and any content that violates the law or infringes on intellectual property). 
  • In some countries, additional use cases are prohibited, which are noted in the SMS Guidelines. 

Opt-In/Opt-Out Requirements

Users must specifically opt in to receive your messages and know how to opt out before you send your first message. 

Note: Twilio’s SMS STOP keyword does not work to automatically stop messaging. You must provide other instructions, such as writing a Support team, calling a Support phone line, or texting another phone number or code to allow users to opt out. 

Formatting Requirements

Please find the formatting requirements for Alphanumeric Sender IDs here.

Note: Some carriers may impose minimum length restrictions on Alphanumeric Sender IDs. This can result in your Alphanumeric Sender ID being modified or replaced by a generic sender ID, i.e. "unknown". 

How to get an Alphanumeric Sender ID 

First, use this page to make sure Alphanumeric Sender IDs are supported for a particular country and to check whether pre-registration is required.

Whether you can get a dynamic Alphanumeric Sender ID or need to pre-register the Alphanumeric Sender ID, you must first validate that the feature is enabled in your account. To do so:

  1. Access the Programmable Messaging page in Console.
  2. Click Settings.
  3. From the General SMS Settings page, Verify that “Alphanumeric Sender ID” is set to Enabled.

To get a dynamic Alphanumeric Sender ID:

If pre-registration is not required, you can instantly get an Alphanumeric Sender ID. 

Simply add the Alphanumeric Sender ID you want in the From parameter in line 4 of the cURL script, as shown in the example below:

curl -XPOST \
-d "Body=Hello from my phone number" \
-d "To=+12685551234" \
-d "From=MyBusiness" \

For details, see Sending Messages: Use an Alphanumeric Sender ID.

 To get a pre-registered Alphanumeric Sender ID:

  1. After you confirm that a country requires pre-registration and click to access the Sender ID Registration form, the first step in that form is to select the country.


  2. Review the specific requirements for that country, as well as any additional needed documents, such as a Letter of Authorization (LOA), screenshots of your user interface, or whatever else may be required.

  3. Download, complete, and then upload any required documents.

  4. Complete the required fields and submit the form.

Once you submit the documents and the form, our Sender ID team will review and submit those materials and keep you informed on the progress of your request via email. 

Using your Pre-registered Alphanumeric Sender ID:

When our Sender ID team has informed you that the pre-registration process is complete, you can use your pre-registered Alphanumeric Sender ID by continuing to pass your Twilio number as the 'from' parameter in your API request and Twilio will dynamically replace the sender ID.

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