Getting Started with Alphanumeric Sender ID for Twilio Programmable SMS

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. This guide explains how alphanumeric sender IDs work, and how to use them with Twilio SMS messaging.

The following topics are discussed in this guide. Click a topic to skip directly to this information:

Benefits of Alphanumeric Sender ID

Some of the key advantages of using Alphanumeric Sender IDs include:

Higher message deliverability: In many countries, regulatory bodies are increasingly clamping down on illegitimate A2P (application-to-person) SMS use cases to curb unwanted messaging.
Once the legitimacy of an A2P use case has been vetted, Twilio handles fluctuating telecom logic, regulations, and carrier-specific rules across 150 countries to ensure your A2P messages reach their destination.

Improved brand recognition: Every SMS sent using a recognizable Alphanumeric Sender ID reinforces your branding.

Increased open rates: With increasing cases of spam and fraud, what appears as the sender of the message is a key factor message recipients take into account when deciding if they should open a message or not. If the sender is an international number, or a number with which they’re not familiar, the chance of a message recipient opening the message is next to none.
With Alphanumeric Sender IDs, receivers immediately recognize the sender, know the message is legitimate, and are 80% more likely to open the message.

Twilio requirements

Alphanumeric Sender ID is automatically supported on all new upgraded (paid) Twilio accounts. It is not supported for free trial accounts.

You can validate that Alphanumeric Sender is enabled on your account by following these steps:

  1. Login to your project at
  2. From the left side navigation bar, click Programmable SMS Icon-ProgSMS.png.
  3. Click Settings.
  4. Verify that "Alphanumeric Sender ID" is set to Enabled.


If you continue to experience issues after validating that you are attempting to send messages to a supported country, your account is upgraded, and Alphanumeric Sender ID is enabled, please contact Twilio Support.

Notice: Spoofing of brands or companies with Alphanumeric Sender ID is not allowed. You must comply with Twilio’s Acceptable Use Policy and Messaging Policy at all times.

Send SMS messages using an Alphanumeric Sender ID

To send SMS messages using an Alphanumeric Sender ID, use the desired ID for the From parameter in your API requests. For examples of how this looks in code, please see Changing the sender ID for sending SMS messages.

You can also enable an Alphanumeric Sender ID on a Twilio Messaging Service. The Alphanumeric Sender ID will be selected automatically when sending to a supported country (unless you have SMS-capable numbers from that country in your Messaging Service pool, in which case Twilio will use those).

Sending limitations

This feature is only available for upgraded (paid) Twilio accounts sending messages to supported countries. Some supported countries have additional requirements like going through a pre-registration process (see which countries require pre-registration) or only allowing messages that are transactional in nature (one-time passwords, account notifications) to be sent using an Alphanumeric Sender ID.

Alphanumeric Sender ID messages sent to an unsupported country will fail with an HTTP 400 error response from Twilio. In this case, we recommend that you fallback to a Twilio international mobile number.

Additionally, recipients cannot reply directly to messages sent out using an Alphanumeric Sender ID.

Prohibited use cases

We have identified the following use cases to be banned from sending messages with alphanumeric sender IDs:

  • Gambling
  • Dating sites
  • Live chats
  • Pornography
  • Antisocial forces and antisocial organization
  • Advertising without Opt-in
  • Harmful to children and teenagers
  • Spam
  • Phishing
  • Scam
  • Infringement of intellectual properties
  • Violations against the law
  • Content deemed to be contrary to public order and morality
  • Pyramid Scheme related

Sender ID registration

Alphanumeric Sender IDs can be registered one of two ways:

  • Dynamic registration
  • Pre-registration

Dynamic Registration countries allow you to use an alphanumeric sender ID on-demand. All you'll need to do is submit the desired sender ID in the From parameter of your API request, instead of using an E.164 formatted Twilio phone number.

Here’s an example cURL script - notice the From parameter updated in line 4.

curl -XPOST \
-d "Body=Hello from MyCompany" \
-d "To=+12685551234" \
-d "From=MyCompany" \

For full details, see Sending Messages: Use an alphanumeric sender ID (Twilio Docs).

Pre-Registration countries require you submit a request at our Alphanumeric Sender ID registration site. Be sure to indicate which country you want to register your ID for. When we receive your request, our Sender ID team will review it, and be in touch to update you on the progress.

Once the Sender ID registration is complete, you can use any Twilio phone number associated with your account as the From parameter in the API request, and Twilio will dynamically replace the Sender ID when we detect the registered country as the sending destination.

Here are examples of common requirements when submitting a Pre-Registration request:

  • The desired Sender ID
  • Intended purpose - one-time passwords, account notifications, promotional messaging, etc.
  • Company name
  • Company website
  • Projected SMS traffic (monthly)

Some countries have additional requirements; for example, in Indonesia, each telecommunication provider requires a Letter of Appointment (LOA) which authorizes Twilio to register and send branded messages on the sender’s behalf. In addition, a screenshot(s) of the page where end users insert their account details and phone number is required, as shown in the illustration below.

Screenshot of Sign Up page required for Indonesia Pre-Registration of Alphanumeric Sender IDs

Notice: For the full list of supported countries and pre-registration requirements, see International Support for Alphanumeric Sender ID.

Please note that this feature is currently unsupported in the North American mainland countries of Canada, the US, and Mexico.

What characters can I use in my Alphanumeric Sender ID?

Alphanumeric Sender ID supports up to 11 characters from the following categories:

  • Upper-case letters A-Z
  • Lower-case letters a-z
  • Numbers 0-9
  • Spaces

Your ID must include at least one letter, and cannot be composed only of numbers. Non-ASCII special characters and punctuation are not allowed.

Notice: India is an exception to this rule; alphanumeric sender IDs must be exacly six characters. For more information, see Twilio's India SMS guidelines.

How much does Alphanumeric Sender ID messaging cost?

There is no price difference for using an Alphanumeric Sender ID vs a standard Twilio phone number. Please see our Programmable SMS Pricing site for complete pricing information.

Notice: Some countries like Russia and Czech Republic have a monthly charge and/or a one-time set-up fee associated with the use of Alphanumeric Sender ID. For full details, see International Support for Alphanumeric Sender ID.

Can users respond to my messages that use Alphanumeric Sender ID?

No, recipients of messages sent with an Alphanumeric Sender ID will not be able to respond to you directly. Because of this limitation, we recommend only using Alphanumeric Sender IDs for one-way outbound messages (such as one-time passwords and account notifications). You may also include a contact number, email, and/or website address in your outgoing messages sent via Alphanumeric Sender ID if you wish to receive responses.

How do users opt out of messages sent with an Alphanumeric Sender ID

Because you can only use Alphanumeric Sender ID for one-way messaging, inbound messages sent to your Alphanumeric Sender ID will not be received on your Twilio project. Due to this limitation, Twilio's SMS STOP keyword filtering does not work for users responding to alphanumeric sender ID messages.

Customers receiving text messages from your Alphanumeric Sender ID should have opted in to your service, and been informed how to opt out before you sent the first message. We recommend you provide your users with a clear description in your Terms of Service about how many messages they should expect to receive, and how they can opt out.

We also highly recommend offering your users the ability to opt out of receiving SMS messages from your service by:

  • Writing to your support team
  • Calling your support phone line
  • Texting another phone number or short code
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