Page tree
Skip to end of metadata
Go to start of metadata


Twilio is a third party service integrated into REDCap that can be used for by research study projects to send survey SMS survey invitations to participants and/or SMS alerts and notifications to participants in relation to survey operations.

The project/study team will need to purchase and fund their own Twilio phone number.

  • Twilio cannot be set up with a non-Twilio phone number.
  • A single Twilio phone # cannot be used for multiple projects.

Feature Type

Optional Module

User Permissions

  • User setting up module will need Project Design and Setup user rights.
  • For survey projects, user will also need Survey Distribution Tools user rights.

Project Status Dependency

  • Recommended
    • Project Status = Development
    • Best practice is to request to enable Twilio while building and testing the project.
  • Permissable
    • Project status = Production
    • Enabling Twilio after a project has been moved to production and started data collection is permissible, but not recommended. It is high impact change that requires custom support for set up and testing.



  • Basics training completed.
  • Survey training completed.


  • Experience building and managing projects.
  • For survey projects, experience building and managing survey projects.

Operations, Set up and Implementation


There are charges for setting up and using Twilio.

Project Set Up 

  • One time fee for projects in development*
    • $225 for investigator initiated research projects.
  • Covers REDCap Admin Team's work to configure the module for the project and train the project personnel on how to use Twilio.

*Enabling Twilio for a project in production requires custom support for which there are additional charges. The exact costs depend on the project's requirements. The REDCap Team meets with the project team to gather details to create an estimate.

Twilio Services

  • Ongoing charges.
  • The project will need to create and fund a unique account, including purchasing phone number, for their project.
    • Twilio cannot be set up with a non-Twilio phone number.
    • If purchasing a toll-free number, Twilio requires additional verification before the number will be approved including:
      • Screenshot of the electronic survey where end users provide their phone number and opt-in to SMS messaging.
      • Photo or screenshot of the keyword or QR code where end users opt-in to SMS messaging.
      • Screenshot documenting if users opt-in to SMS messaging via voice, such as a checkbox on a form.
      • Scan or photo of the paper form where end users opt-in to SMS messages.
  • Twilio charges for each message sent and received.
  • Twilio pricing links

Regulatory Considerations

Study teams will need to modify their protocol to included using Twilio to communicated via SMS with their participants.

Protocol Language

  • Survey invitations and reminders will be sent by email or SMS text message (specify the method(s)) to study participants.

Participant Consent Language

  • When the study team sends you a survey invitation or reminder by text message, your phone number will be shared with Twilio, Inc.. No other data will be shared.

Request Twilio for Your Project

Click on the Request Twilio blue button in your project's Project Setup tab > Optional Modules section.

Billing information will be collected at request, including Alias and FAID numbers and the name of the FAID owner.

Twilio Phone Number 

  • A Twilio phone # required to use Twilio in your REDCap project.
    • Twilio cannot be set up with a non-Twilio phone number.
    • Twilio can only be used to text survey invitations. Voice capability not needed and cannot be used.

  • A single Twilio phone # cannot be used for multiple projects.
    • Each individual REDCap project required to have a unique Twilio #.

  • Twilio #s are not monitored for incoming texts or phone calls.
    • By default, incoming texts or calls from participants to your Twilio # are redirected to the url:, which is not intended for Twilio use.
    • The REDCap team can set up a generic response for incoming texts instructing participants to contact the study team.

Project Configuration

The REDCap Team enables and configures Twilio based on the following determinations from project team:

  • Twilio account information submitted during the Twilio request process.
  • The default preference sending survey invitations: Email or SMS.
    • This value will be used as the pre-selected delivery preference for all participants added to the project (once Twilio has been enabled and configured for the project).
  • A phone number validated field in a data collection form or survey, used for capturing the participant's phone number.
  • Participant Managed Invitation Preference
    • Add a radio button or drop-down field to a survey to allow your participants to manage their default preference for receiving survey invitations for your project.
    • The field label and variable name are defined at the user's discretion. 
    • The required options are as follows (raw value, label)
      EMAIL, Email invitation
      SMS_INVITE_WEB, SMS invitation (contains survey link)
    • Configure your Twilio settings to map the field to the new option, Control each participant's invitation preference using a multiple choice field.

Participant Phone Number

  • REDCap only supports designating a single phone number for a participant to receive SMS survey invitations.
  • Unlike email, you cannot designate, in an individual survey setting,  a phone number for sending survey SMS invitations.

Survey Distribution

The following two settings define survey distribution for projects using Twilio.

Participant Preference

  • Once Twilio has been enabled and configured for the project, the participant's preference for survey invitation defaults to the preference defined in the Twilio configuration, as described above.
  • The participant preference is a project level setting and cannot be modified at the individual survey level.
  • The participant's preference is stored in the Survey Distribution Tools > Participant List.
  • The participant’s preference can be changed via Participant List > Invitation Preference.

Survey Invitation Delivery Method

  • All survey invitations have an Invitation Type, which defines the mechanism for sending the invitation to the participant.
  • For projects using Twilio, there are 3 Invitation Types:
    • Email
    • SMS
    • Use participant's preference
  • Automatically Schedules Invitations (ASI's)
    • The Invitation Type defaults to email.
    • The Invitation Type selected for a particular ASI will apply to all the invitations sent by that ASI as follows.

      Invitation TypeParticipant PreferenceInvitation Sent Via
      Use participant's preferenceEmailEmail
      Use participant's preferenceSMSSMS
  • On Demand and Manually Scheduled Invitations
    • These are invitations set up via the Participant List > Compose Invitations or from the individual record via Survey > Survey Options drop-down > Compose Invitations
    • Participant List > Compose Invitations
      • The Invitation Type defaults to Use participant's preference.
      • The Invitation Type selected for a the specific survey invitation will apply to all the participants you select to send the invitation to.
    • Survey > Survey Options drop-down > Compose Invitations
      • The Invitation Type defaults to the participant's preference.
      • You can select a different Invitation Type than the participant's preference.

SMS Survey Invitations

  • Twilio splits messages over 160 characters into 153 character segments, which it sends as separate messages.
    • Split segment messages recombined on the recipient's device.
    • Twilio bills per split segment message.
  • REDCap adds survey links to messages depending on the smart variables the builder embeds in the message, [survey-url] or [survey-link].

  • For SMS invitations [survey-link] is typically transformed into a clickable URL

  • The smart variable url or link cannot be edited.

  • The URL is approximately 50 characters.
  • The URL character length should be factored into the length of the message.

Save & Return Notifications

  • The Save & Return message, generated by REDCap, is sent to the participant’s email address, as designated in REDCap, not their phone number.
  • If an email address has not designated for the project or the survey, the participant will be prompted to enter an email address to receive the Save & Return message.

Alerts and Notifications

  • SMS messaging is enabled for the Alerts and Notifications module.
  • You can send an SMS alert or notification to a participant, mapping to any phone validated field in the participant's record.

Monitoring Your Twilio Number

Twilio #s are not monitored for incoming texts or phone calls.

  • By default, incoming texts or calls from participants to your Twilio # are redirected to the url:, which is not intended for Twilio use.
  • The REDCap Team will help you set up a generic response that will refer participant's to the study teams generic or shared email address or phone number.
    • Manage incoming messages to your phone number via TwilML Bin
    • Find the TwilML Bin in the Developer Tools section.
    • Message Syntax
    • <?xml version="1.0" encoding="UTF-8"?>
      <Message>Your contact info</Message>

  • No labels