Number Masking PIN-based Authentication


Plivo’s number masking solution utilizes an intermediary virtual number to preserve the anonymity of both parties during a call. Customers can initiate a number masking session with pre-registered first and second-party numbers. Nonetheless, situations may arise where a caller might use a number not previously included in the masking session. To accommodate such instances, Plivo introduces PIN verification as a means to authenticate and seamlessly connect these callers.


Plivo’s session object assigns unique PINs to both call participants. If an unregistered caller dials the virtual number, the Number Masking API prompts this caller to verify their identity using a PIN. The caller is connected once the PIN is successfully authenticated.

Participants have two options for setting PIN numbers:

  • They can either set their own unique PINs, or
  • Allow Plivo’s Number Masking API to generate and assign PINs

For more details on PIN-related parameters, please refer to our session object


When a registered caller dials the virtual number, Plivo seamlessly connects the call without requiring further authentication. However, if a caller dials the virtual number from an unregistered number, Plivo prompts the caller to enter their PIN for authentication purposes. This authentication is necessary for Plivo to connect the caller to the call. If the entered PIN matches the first party’s PIN, the call is connected to the second party, and vice versa.


For improved tracking and asynchronous updates, Plivo sends PIN authentication status callbacks to your application server. This record allows you to monitor successful and failed interactions. PIN authentication callbacks also provide visibility into the percentage of interactions occurring from registered and unregistered numbers for further analysis. Refer to session callbacks for more details on PIN authentication status-related callback attributes.