> ## Documentation Index
> Fetch the complete documentation index at: https://help.atlas.kitchen/llms.txt
> Use this file to discover all available pages before exploring further.

# Using SMS with Atlas and Customer.io

> Connect your own Twilio sender to Customer.io to send loyalty SMS, order confirmations, and one-time passcodes to your customers.

<Info>
  **Who is this for?**

  * Atlas merchants who use Customer.io for marketing
  * Merchants who want to reach customers by SMS
</Info>

## What this does

This connects your Twilio account to Customer.io. Your customers receive SMS messages sent from your own Twilio sender.

Use this for loyalty messages, order confirmations, and one-time passcodes.

## When to use this

* You want to send loyalty SMS to customers who have opted in
* You need to send order confirmations or one-time passcodes by text
* You are setting up or already have a Twilio account

## Steps

<Steps>
  <Step title="Set up a Twilio account">
    Go to [twilio.com](https://www.twilio.com/en-us) and sign up for a paid account.

    Once your account is active, buy a sender. You have two options:

    * **Phone number**: Buy a local number from Twilio.
    * **Alphanumeric Sender ID**: Use your brand name as the sender (for example, `ATLAS`). Not available in all countries.

    <Warning>
      **Singapore merchants using an Alphanumeric Sender ID**: You must register your sender ID with the SGNIC SMS Sender ID Registry (SSIR) before sending. Without registration, your messages may appear as "Likely-SCAM" on recipients' phones. Register at [sgnic.sg/faq/sms-sender-id-registry](https://www.sgnic.sg/faq/sms-sender-id-registry).
    </Warning>

    In the Twilio Console, go to your account settings and copy your **live** Account SID and Auth Token. Do not use test credentials — they do not send real messages.
  </Step>

  <Step title="Connect Twilio to Customer.io">
    In Customer.io, go to **Workspace Settings**, then click **SMS**.

    Enter your Twilio credentials in the fields provided:

    ```plaintext theme={null}
    Account SID:   ACxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
    Auth Token:    xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
    ```

    Enter your sender phone number or Alphanumeric Sender ID.

    Click **Save**.
  </Step>

  <Step title="Add SMS to a campaign or newsletter">
    Choose how you want to send SMS in Customer.io:

    * **Campaign workflow**: Drag an SMS action into a workflow. Use this for automated loyalty messages triggered by a customer action.
    * **SMS newsletter**: Create a one-time broadcast to a segment of customers. Use this for promotions and announcements.
    * **Transactional SMS**: Send order confirmations or one-time passcodes. Use this for time-sensitive messages.
  </Step>
</Steps>

## What should happen

* Customers receive SMS messages from your Twilio sender.
* Loyalty messages arrive within seconds of being triggered in Customer.io.
* Customer.io shows a delivery status for each message sent.

## If it doesn't work

<AccordionGroup>
  <Accordion title="Messages are not sending">
    1. Check that you entered your **live** Account SID and Auth Token. Test credentials do not send real messages.
    2. Confirm your Twilio account is paid and active, not on a trial.
    3. Open the Twilio Console and check for error codes on failed messages.
    4. Make sure your sender number or Alphanumeric Sender ID is active in Twilio.
  </Accordion>

  <Accordion title="Messages appear as 'Likely-SCAM' in Singapore">
    Register your Alphanumeric Sender ID with the SGNIC SMS Sender ID Registry before sending. See Step 1 above for the registration link.
  </Accordion>

  <Accordion title="Customers are not receiving messages">
    1. Confirm customers have opted in to SMS communications.
    2. Check that each customer's phone number includes the correct country code.
    3. Review the delivery log in Customer.io for failed deliveries.
  </Accordion>
</AccordionGroup>

If the issue persists, contact support at [hello@atlas.kitchen](mailto:hello@atlas.kitchen).

## What's next

* [Set up your loyalty programme](/merchant-portal/loyalty-signup)
* [Manage your customer data](/merchant-portal/customers-data)