SMS Verify API

The SMS Verify API delivers phone-based verification and two-factor authentication using a limited duration, one-time passcode sent over SMS.


To send SMS messages for other purposes besides delivering verification codes, use the TeleSign SMS API, not this one.

Common Use Cases:

  • Two Factor Authentication (2FA) - Prompt a user, after entering their password, to enter a verification code you send to their phone number to complete a log-in process.
  • Password Reset - Ask a user to enter a verification code you send to their phone number; if they enter it correctly, allow that user to reset their password.
  • Verification - Make sure a user is not entering a fake phone number, by sending a verification code to their phone and asking them to enter it in.

General Requirements

  • Base URL:
  • Protocols: https
  • Authentication: Basic (easiest to implement) or Digest
  • Encoding: Accepts only UTF-8 unicode characters as inputs.
  • Accepts: application/x-www-form-urlencoded
  • Responds With: application/json
  • Required Headers: Content-Type - application/x-www-form-urlencoded

Documentation by Category

  • Reference: Go here if you are familiar with the API at a high-level, and want to look up technical specs for the API and each of its actions.
  • How-to Guides: Go here if you are familiar with basic usage of the API, and want instructions to carry out one specific task with it.
    • Verify By SMS With Your Own Code - This page walks you step-by-step through how to use the SMS Verify API to send your own verification code to an end-user. It also explains how to complete verification and send us completion data to improve the service.
    • Verify By SMS With TeleSign Code - This page walks you step-by-step through how to use the SMS Verify API to send an SMS to an end-user with a verification code generated by TeleSign. It also explains how to test if input from an end-user matches that code, so you can complete verification.
    • Screen SMS Verify Recipients by Risk Score - This page walks you step-by-step through how to screen out potentially fraud-related SMS Verify recipients using a risk score before sending them a verification SMS.
  • Explanations: Go here to clarify or expand your understanding of a particular topic related to this API. These pages might help you make an implementation or usage decision, or simply deepen your knowledge.

An SMPP implementation may be better for you than using the REST API if you need extremely high throughput, but the integration requires a higher level of technical expertise and may take longer.

Other Resources

  • Try It - Use a widget to make some test requests without writing any code.
  • Compliance - Learn SMS compliance best practices from these articles in our Support Center.

Compliance with regulations in some countries may require you to give the end-user a way to reply to your message. To add this feature to your integration, you can use the TeleSign Inbound SMS service.