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Alphanumeric Sender ID for Twilio Programmable SMS

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 numeric longcode 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 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 “registered

Which Countries Support Alphanumeric Sender IDs?

You can find out which countries support Alphanumeric Sender IDs on this page.


There is no additional charge for using an Alphanumeric Sender ID for most countries. However, for some countries that require 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 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: End users cannot send replies like "STOP" to Alphanumeric Sender IDs. 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 Use an Alphanumeric Sender ID

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

Whether you can use a dynamic Alphanumeric Sender ID or need to 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.

Use a Dynamic Alphanumeric Sender ID (Registration Not Required)

If registration is not required, you can instantly use an Alphanumeric Sender ID. We refer to this as a dynamic 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" \

Register an Alphanumeric Sender ID

See this article for a guide on registering Alphanumeric Sender IDs.

Using your Registered Alphanumeric Sender ID

Once you’ve registered your Alphanumeric Sender ID, you can pass it directly into the From value of your API Request. Be sure to match the registered Alphanumeric Sender ID exactly because in many cases SMS carriers will check for case-sensitive matches on registrations.

If your application is set up in such a way that a phone number or other unregistered sender could be passed as your From parameter instead of the registered Alphanumeric Sender ID, then you can configure one of your registered Alphanumeric Sender IDs as a Default Sender ID for a country. The Default Sender ID will be used to overwrite your From parameter at send time in any case that the From value doesn’t match a registered Alphanumeric Sender ID for that destination. See here for more details.

Registered Default Sender IDs in Messaging Logs and Insights

If you set a registered Sender ID as your Default Sender ID for a country, we automatically replace the value provided in the “From” parameter of the API Request with your Default Sender ID for all messages sent to that destination only when the “From” value does not match any of your other registered Sender IDs for that destination. You can read more about the Default Sender ID here.

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