Overview

Send SMS messages through your agent using Twilio.

Prerequisites: You need a Twilio account. See the Twilio integration guide.

The “Integrating SMS into a function” section requires Python. Setting up templates and sending SMS from Managed Topics actions is fully no-code. The conv.send_sms and conv.send_sms_template function examples at the bottom of this page are for developers.

Use SMS when your agent needs to send callers something they can refer to after the call — a link, confirmation number, appointment details, or directions. SMS bridges the gap between a voice conversation and a persistent written record.

Create and manage SMS templates in Build > SMS.

Setting up messaging

Connect your Twilio account

1. Go to Build > SMS in the sidebar.

2. Click Connect Twilio Account.

3. In the pop-up form, fill in the following fields:

   • Account SID: Find this in the “Account Info” section of your Twilio dashboard.
   • Auth Token: Retrieve this from your Twilio account settings.
   • Twilio Phone Number: Provide the number you wish to use for sending SMS messages.

4. Click Connect to link your Twilio account.

   

A2P 10DLC registration (US and Canada)

If you are using a US or Canadian Twilio number, you must register for A2P 10DLC to comply with carrier regulations. Without registration, Twilio blocks SMS messages entirely.

A2P 10DLC registration can take several weeks and campaigns are frequently rejected. Start this process early — do not wait until launch.

Register

1. Go to Twilio’s A2P 10DLC registration page: Twilio A2P 10DLC Registration Guide
2. Complete brand and campaign registration to comply with US and Canadian carrier regulations.
3. Wait for approval. This typically takes several weeks. Twilio has become increasingly strict with approvals.
4. Once approved, messages will send successfully.

Campaigns are often rejected for vague opt-in descriptions. Include detailed example conversation transcripts showing how callers consent to receiving SMS. Linking a document with full sample transcripts significantly improves approval rates.

A2P 10DLC is specific to US and Canadian numbers. UK and other international numbers have separate regulatory requirements — check your local carrier guidelines.

Troubleshooting: If your messages fail to send, check the Twilio logs for these error codes:

• 30034 - Unregistered Number
• 30035 - Number Still Being Configured

Add SMS templates

Once connected, follow these steps to create SMS templates:

1. Click Add SMS in Build > SMS.
2. Fill in the form:
   • Title: A descriptive name for the SMS template (e.g., reservation_confirmation). This is the name you reference when triggering the template in functions. Max 100 characters.
   • SMS Body: The content of the message. Max 500 characters. Supports dynamic tokens (see below).
   • Phone Number: Choose the Twilio phone number associated with this message.
3. Save the template to make it available during conversations.

Messages of 160 characters or fewer are sent as a single SMS segment. Longer messages are split across multiple segments, which may increase cost. Keep templates concise where possible.

Per-environment phone numbers

Each SMS template can use a different Twilio phone number per environment. This allows you to test SMS in sandbox with a test number while using a production number in Live.

The phone number you select in the template form applies to the Live environment. Sandbox and pre-release environments can be configured separately. This prevents test messages from being sent from your production number during development.

Messaging Service IDs

In addition to phone numbers, you can use a Twilio Messaging Service ID (format: MG followed by 32 hex characters) instead of a direct phone number. Messaging Services allow Twilio to manage number selection, compliance, and scaling automatically. This is useful for high-volume deployments.

Dynamic tokens

You can insert dynamic values into SMS templates using the following syntax:

Token type	Syntax	Example
Variant attributes	${attribute_name}	${property_name}
Entities	{{entity:entity_name}}	{{entity:booking_date}}
Variables	{{vrbl:VARIABLE_ID}}	{{vrbl:CONFIRMATION_CODE}}

Example template body:

Hi ${customer_name}, your reservation at ${property_name} is confirmed for {{entity:booking_date}}.

For multilingual projects, consider creating separate templates with language suffixes (e.g., confirmation_en, confirmation_es).

Managing templates

All created SMS templates are listed in Build > SMS. You can:

• Edit: Modify the title, message content, or associated phone number.
• Duplicate: Quickly create a copy of an existing template for similar use cases.
• Delete: Remove unused or outdated templates.

Using an SMS template

1. Go to Build > Knowledge > Managed Topics tab

   • Ensure you are on the Managed Topics tab.

2. Add an action to a Managed Topic card

   • In any Managed Topic card, click “Add Actions.”

3. Set SMS action

   • Prompt something like “If someone asks for more details, send” in the action box.
   • Click the + button on the right-hand side of the box and choose SMS > {SMS template title}.

   Here’s an example of how to construct a prompt for your agent to send an SMS:

   After the user confirms that they would like to receive an SMS message with further details, call {{SMS_template}} to send the SMS out.
   

4. Click ‘Save’ and ‘Publish’

Best practices

• Keep messages short and relevant — 160 characters or fewer sends as a single segment.
• Use variant attributes or dynamic fields (e.g., customer name, booking details) to personalize messages.
• Follow SMS regulations, including providing opt-out options when required.

Example: Integrating handoffs with SMS

Combine handoff functionality with SMS:

1. The agent transfers the user to a specific agent or team using Handoffs.
2. At the same time, an SMS template is triggered, sending the user additional details or confirmation of the transfer.

Integrating SMS into a function

SMS can be triggered as part of a function using the conv object:

conv.send_sms

Sends a free-form SMS message to a specified phone number.

# Send to the current caller
conv.send_sms(conv.caller_number, "Your appointment is confirmed for tomorrow at 2pm.")

conv.send_sms_template

Sends a pre-configured SMS template by template name (the title you defined in Build > SMS).

# Send a template to the current caller
conv.send_sms_template(conv.caller_number, "reservation_confirmation")

The second argument is the template name (the title from Build > SMS), not an ID. For example, if your template is titled prescription_refill, use conv.send_sms_template(conv.caller_number, 'prescription_refill').

conv.send_sms_template queues the SMS for delivery rather than sending it synchronously. This means try/except blocks will not catch delivery failures — the call returns successfully even if the SMS later fails to send. To verify delivery, check conversation metadata or the Standard dashboard SMS widget.

Want to trigger SMS from Python? This page has a developer section covering conv.send_sms and conv.send_sms_template. Switch to Full docs in the top navigation to see it.

Delivery and logging

• Successful SMS sends are logged in the conversation metadata.
• Failed sends increment the API Failures metric.
• Use the SMS widget on the Standard dashboard to monitor delivery rates.

Related pages

Managed Topics actions

Trigger SMS sends from Knowledge topic actions.

Twilio integration

Connect your Twilio account to enable SMS.

Standard dashboard

Monitor SMS delivery rates with the SMS widget.