With Callr Actions, you can send an SMS dynamically as part of any voice flow — for example, to:

• Notify a caller who couldn’t reach you
• Send confirmation or follow-up messages
• Share a URL, form, or next step
• Log important info or trigger SMS-based workflows

All of this is handled directly in YAML, using the sms@v1 action.

⚠️

Reminder

If you are in Build Mode, you can only send SMS to Testing Numbers — phone numbers you own and have verified. Make sure to add your personal number as a Testing Number in the Callr Portal.

📲 Example: Missed Call Follow-up

In this scenario, we try to forward the call to someone. If the call fails and the caller is using a mobile number, we automatically send them a follow-up SMS.

branches:
  inbound-call:
    actions:
      - action: dial@v1
        params:
          targets:
            - number: "+33199001234"
              timeout: 25
          answerOnBranch: answered
        result: $dial

      - if: "!$dial?.ok"
        goto:
          branch: voicemail

  voicemail:
    actions:
      - if: call.fromType.match(/MOBILE/)
        action: sms@v1
        params:
          to:
            - ${{ call.fromNumber }}
          body: >
            Hello! You tried to reach us but we weren’t available.
            We’ll get back to you as soon as possible.

🧠 How It Works

• We attempt to connect the call using dial@v1
• If the call fails (e.g., timeout, busy, unreachable), we jump to the voicemail branch
• We check if the caller is using a mobile number (fromType.match(/MOBILE/))
• If true, we send an SMS using sms@v1

💡

You can customize the SMS body dynamically using expressions or pre-defined variables like call.fromNumber, call.toNumber, etc.

⚙️ Advanced Options

The sms@v1 action supports several optional parameters that let you fine-tune delivery and compliance.

🆔 from – Customize the Sender ID

You can personalize the Sender ID using the from field:

action: sms@v1
params:
  # ... other parameters
  from: "<sender>"

• Leave it empty to let Callr assign a default based on destination
• Set it to:
  • A phone number (e.g., +33639980042)
  • An alphanumeric sender (up to 11 characters, at least one letter)

⚠️

Important

Custom SMS senders must be approved by Callr and supported by the destination carrier.
Some destinations require regulator approval for sender IDs. 👉 Request custom sender approval here

🧾 encoding – Control Message Encoding

By default, encoding is automatically detected based on the characters in your SMS body.

You can override this with:

action: sms@v1
params:
  # ... other parameters
  encoding: "gsm"     # or "unicode"

• gsm (default): Allows up to 153 characters per part
• unicode: Supports special characters, emojis, etc., but limits to 67 characters per part

⚠️

Important

Some countries only support GSM encoding. We recommend using GSM for maximum deliverability unless you specifically need Unicode characters.

🏷️ trafficType – Set Message Intent

You can specify the type of traffic you are sending. This is required by some carriers for proper delivery and compliance:

action: sms@v1
params:
  # ... other parameters
  trafficType: "alerting"  # or "marketing"

• marketing (default): Promotional or non-urgent content
• alerting: Time-sensitive or critical content (e.g., OTPs, service alerts)

✨ Pro Tips

• ✅ Always validate the number type before sending SMS — landlines may reject or ignore SMS
• 🧪 Use call.fromType, call.fromCountry, or call.cdr.status to fine-tune logic
• 🔐 Consider using fetch@v2 + sms@v1 together to personalize the message (e.g., fetch user name, order info, etc.)

🔗 Use Cases

• Missed call notifications
• Callback confirmations
• Delivery alerts or appointment reminders
• Conversational opt-in flows (voice → SMS)
• Multichannel journeys (start on voice, continue on SMS)