Core Forms
Get Core Forms

Twilio SMS Integration

Send an SMS notification via Twilio when a form is submitted.

Action type: twilio_sms Class: Core_Forms\Actions\TwilioSms Source: src/actions/class-twilio-sms.php

Setup

  1. Sign up at twilio.com and get your Account SID and Auth Token from the console dashboard.
  2. Purchase or configure a phone number in Twilio to send from.
  3. In WordPress, edit your form > Actions tab > Add Action > Send SMS (Twilio).
  4. Enter Account SID, Auth Token, From Number, To Number, and optional message.

Settings Reference

Setting Required Default Description
Account SID Yes -- Twilio Account SID
Auth Token Yes -- Twilio Auth Token
From Number Yes -- Twilio phone number to send from (E.164 format: +1234567890)
To Number Yes -- Recipient phone number or [field_name] variable
Message No All fields Custom message template

Dynamic To Number

The To Number field supports data variables. Use a form field name in brackets to send the SMS to the number submitted by the user:

[phone]

This replaces [phone] with the value of the phone form field, allowing per-submission SMS delivery (e.g., order confirmations, appointment reminders).

Message Variables

Use these variables in the Message field:

  • [all:label] -- all submitted fields as "Label: Value" pairs
  • [NAME] -- value of the "name" field
  • [field_name] -- value of any form field

Auto-Generated Message

When the Message field is left empty, all fields are sent as plain text:

Contact Form -- New submission
Name: Jane Smith
Email: jane@example.com
Message: I'd like to learn more.

SMS Length

Messages are truncated to 1,600 characters (Twilio's concatenated SMS limit). Standard SMS segments are 160 characters; longer messages are split into multiple segments and may incur additional charges.

Authentication

Twilio uses HTTP Basic authentication: base64(AccountSID:AuthToken). The request is sent to:

https://api.twilio.com/2010-04-01/Accounts/{SID}/Messages.json

How It Works

  1. Validates all required fields (SID, token, from, to).
  2. Replaces data variables in the To Number field.
  3. Builds the message (auto-generated or custom with variable replacement).
  4. Truncates the message to 1,600 characters.
  5. POSTs to the Twilio Messages API with Basic auth.
  6. The body is sent as form-urlencoded (Twilio API requirement): From, To, Body.
  7. The request times out after 15 seconds.
  8. Returns true on success.

Example: Order Notification to Admin

  • From Number: +15551234567
  • To Number: +15559876543
  • Message: New order from [NAME] ([EMAIL]). Amount: [total]

Example: Confirmation to Submitter

  • From Number: +15551234567
  • To Number: [phone]
  • Message: Thanks [NAME]! We received your request and will respond within 24 hours.

Troubleshooting

  • SMS not delivered: Verify the From Number is a valid Twilio number with SMS capability.
  • Invalid To Number: Phone numbers must be in E.164 format (+1234567890). If using a field variable, ensure the form collects numbers in this format.
  • Trial account limits: Twilio trial accounts can only send to verified phone numbers.
  • Charges: Each SMS segment costs money. Monitor usage in the Twilio console.