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Use this guide when you want OTP.ID to deliver an outbound SMS OTP. You send channel: "sms" to both POST /v3/request and POST /v3/send, and OTP.ID sends the message to the phone number you provide. SMS is a strong fit when you want a simple code-entry experience. The user receives a text message on the destination phone number, so the flow works without an installed messaging app or mobile data connectivity. Use an international phone number in digits-only format so OTP.ID can reach the correct destination.

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How the flow works

1

Create the OTP request

Call POST /v3/request with channel: "sms" when you want OTP.ID to generate the code for you.
2

Or send your own code

Call POST /v3/send with channel: "sms" when your application already has the code.
3

OTP.ID sends an SMS message

OTP.ID delivers the OTP as an outbound SMS to the destination number you submitted.
4

The user enters the code

Show a clear OTP entry UI in your app and let the user type or paste the code from the text message.
5

You verify the code

Submit the transaction ID and code through the verification flow described in the Verify OTP guide.

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Request example

This example uses the canonical request shape in the POST /v3/request API reference.

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What your UI should do

  • Use a single OTP input or six separate digit boxes so the user can enter the code quickly.
  • Show a resend action, but only after your own cooldown expires.
  • Show the expiry time clearly so the user knows when the current code stops working.
  • If delivery fails, tell the user to request a new code instead of retrying the same message automatically.
  • Keep the verification action near the input so the user can finish the flow without leaving the screen.