Adding SMS codes to Dropbox Sign signature requests

Updated Sep 26, 2025

In this article

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This article describes a feature available to Dropbox Sign customers on Standard and Premium API plans. 

Signature requests sent with SMS verification require signers to enter a verification code in order to access and complete the request.

How to set SMS verification

SMS verification can be set by adding the signers[%i%][sms_phone_number] request parameter to requests made to the following endpoints:

  • /signature_request/send
  • /signature_request/send_with_template
  • /signature_request/create_embedded
  • /signature_request/create_embedded_with_template
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Note: SMS verification is not available in test mode.

The signer’s experience

When SMS verification has been set for a signature request, signers will be prompted to request a code in order to proceed with the request.

If an incorrect code is entered, the signer will see an error message.

Signers have the option to have the code re-sent to their number by clicking Send new code. If the signer has any issues, they can contact the sender of the document by clicking the sender's email address.

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