Sender ID setup

This guide walks you through how to register a sender ID in Sender for the first time so recipients can identify your business when they receive an SMS.

Where to find this feature

In the Sender dashboard, go to: Account settings → SMS settings

This opens the Phone numbers page. Here you will see a table listing all registered sender IDs with their use case, status, and date added. Above the table is the Add phone number button used to register a new sender ID. Below the table is the SMS Message Add-ons section, where you configure your organizational prefix, opt-out text, and opt-out link text.

Steps to set up a sender ID

Step 1 — Choose a sender type

Click the Add phone number button in the top-right corner of the Phone numbers page. This opens the Choose a sender type screen with two options.

Toll-free number — Recipients see a phone number in +18xx format. Available in the United States and Canada. Supports two-way messaging.

Alphanumeric ID — A custom brand name (e.g., “APPLE”) that appears as the sender. One-way messaging only, meaning recipients cannot reply. Available outside the US and Canada.

Select the option that matches your region and messaging needs, then proceed to the next section of the page.

Step 2 — Configure your sender ID details

The configuration depends on the sender type you selected in Step 1.

If you selected Toll-free number: A list of available toll-free numbers appears under Choose your toll-free number. Click one of the numbers to select it. The selected number will be the phone number your recipients see when they receive your SMS.

If you selected Alphanumeric ID: A Sender ID text field appears. Enter your business or brand name (up to 11 characters). This name will display as the sender on recipients’ devices. Note the limitations listed on the page: alphanumeric sender IDs do not support multimedia (MMS) or two-way messaging.

Step 3 — Register your sender ID

Review the TCPA & CTIA compliance information displayed at the bottom of the page. This section lists content categories that are prohibited when sending SMS through Sender, including S.H.A.F.T. content, drugs and vaping, gambling, and high-risk finance.

Once you have confirmed your sender type and details, click the Get started button. You will be redirected to the Phone numbers page, where your new sender ID appears in the table with an In Progress status and a Promotional use case.

Step 4 — Configure SMS Message Add-ons

On the Phone numbers page, scroll down to the SMS Message Add-ons section. Configure the following three fields:

Organizational prefix — Enter your business name or a recognizable identifier. This prefix is added to outgoing SMS messages so recipients know who the message is from.

Opt-out text — Enter an opt-out instruction such as Reply STOP to optout. This text must include the word “STOP.” It is appended to your SMS messages to provide recipients with a way to unsubscribe.

Opt-out link text — Enter unsubscribe link text such as Unsubscribe: {$unsubscribe_link}. This provides an alternative opt-out method via a clickable link.

Click Update to save your SMS Message Add-ons configuration.

SMS compliance requirements

TCPA (Telephone Consumer Protection Act) — Applies to SMS sent to recipients in the United States. Requires explicit prior consent from subscribers before sending marketing text messages. Sender’s signup forms and opt-in tools help you collect and document consent. Consult a legal professional for jurisdiction-specific requirements.

CTIA (Cellular Telecommunications Industry Association) guidelines — Industry standards enforced by US carriers. Prohibit specific content categories including S.H.A.F.T. content (sexual, hateful, alcohol, firearms, or tobacco-related content), drugs and vaping, gambling, and high-risk finance. Sender displays these restrictions during sender ID registration and does not allow sending this content.

GDPR (General Data Protection Regulation) — Applies when sending SMS to recipients in the European Union. Requires a lawful basis for processing personal data, which for marketing SMS typically means explicit opt-in consent. Recipients must be able to withdraw consent easily. Consult a legal professional for guidance specific to your jurisdiction.

Opt-out requirements — Most carrier regulations and Sender’s own SMS policies require that every marketing SMS includes opt-out instructions. Sender provides the Opt-out text and Opt-out link text fields in SMS Message Add-ons to help you meet this requirement. The opt-out text must contain the word “STOP.”

Sender’s prohibited content policy — Sender does not permit sending SMS containing S.H.A.F.T. content, drug or vaping promotions, gambling content, or high-risk financial offers. These restrictions are displayed during sender ID registration and apply regardless of your target country.

Always consult a legal professional for advice specific to your jurisdiction and use case before launching SMS campaigns.

What happens next

After registering your sender ID, it will appear on the Phone numbers page with an In Progress status while it is reviewed and approved. Once approved, the status will update, and you can use it to send SMS campaigns.

To verify your setup, create a test SMS campaign from SMS campaigns and send it to your own phone number. Confirm that the message arrives, the sender ID displays correctly, and the opt-out text appears as expected.

You can manage all registered sender IDs, add new ones, or delete existing ones from Account settings → SMS settings at any time. Your registered sender ID will be available for selection when creating SMS campaigns or automations.

Common issues

Sender ID shows “In Progress” status → Your sender ID is pending review or approval. Wait for the status to update before attempting to send SMS campaigns. If the status does not change after an extended period, contact Sender support.

“Phone number already taken” error → The sender ID name or number you entered is already registered on your account or by another user. Choose a different alphanumeric name or select a different toll-free number from the available list.

Alphanumeric ID not available in your target country → Some countries, including the United States and Canada, do not support alphanumeric sender IDs due to carrier restrictions. Select Toll-free number instead if you are sending to recipients in those regions.

Opt-out text not saving → The Opt-out text field must include the word “STOP.” Ensure your opt-out message contains “STOP” (e.g., Reply STOP to optout) before clicking Update.

SMS not displaying sender ID correctly → Carrier networks in certain countries may override or modify the displayed sender ID. This is a carrier-level behavior outside Sender’s control. Send a test SMS to verify how your sender ID appears on recipient devices.

FAQs

What is a sender ID? A sender ID is the name or phone number that appears as the sender when recipients receive your SMS. In Sender, you can register either a toll-free phone number (available in the US and Canada) or an alphanumeric ID using your brand name (available outside the US and Canada, up to 11 characters).

What is the difference between a toll-free number and an alphanumeric ID? A toll-free number is a phone number in +18xx format that supports two-way messaging, meaning recipients can reply. An alphanumeric ID is a custom brand name that supports one-way messaging only — recipients cannot reply or send messages back. Toll-free numbers are available in the US and Canada, while alphanumeric IDs are available outside those regions.

Do I need consent to send SMS messages? Yes. SMS regulations like TCPA (US) and GDPR (EU) require explicit consent from recipients before sending marketing SMS. Collect consent through signup forms with a clear opt-in statement. Consult a legal professional for guidance specific to your jurisdiction.

What should I include in every SMS message for compliance? Every marketing SMS should include opt-out instructions, such as “Reply STOP to unsubscribe.” This is required by most carrier regulations and Sender’s own SMS policies. Configure your default opt-out text in Account settings → SMS settings under SMS Message Add-ons.

How long does sender ID approval take? After registration, your sender ID appears with an In Progress status. Approval times vary depending on the sender type and region. Monitor the Status column on the Phone numbers page for updates, or contact Sender support if approval is delayed.

Can I register multiple sender IDs? Yes. You can register multiple sender IDs by clicking Add phone number on the Phone numbers page. Each sender ID will be listed in the table with its own status and use case.

Are there SMS sending restrictions by country? Yes. Some countries have specific carrier restrictions on sender ID types, content, or sending hours. For example, the US and Canada do not support alphanumeric sender IDs. Check Sender’s SMS documentation or contact support for details about restrictions in your target countries.

What phone number format does Sender require for subscribers? Phone numbers must be stored in international format with the country code prefix (e.g., +1 for the United States, +44 for the United Kingdom). Ensure subscriber phone number fields include the full international format.

How do I test my SMS setup? After your sender ID is approved, create a new SMS campaign from SMS campaigns and send a test message to your own phone number. Verify that the message arrives, the sender ID displays correctly, and the opt-out text appears as expected.