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This guide walks through how number masking connects two parties while keeping their real phone numbers private.

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Call Flow

Suppose you have a web or mobile application that needs to connect two participants in a voice call.
1

Collect phone numbers

Your application collects the phone numbers of two participants whose numbers you want to mask.
2

Create a masking session

Your application sends these phone numbers to Plivo’s Number Masking API.
3

Receive virtual number

Plivo creates a session and assigns a virtual phone number from your account.
4

Connect the parties

Display the virtual number to both participants. When either party calls it, they’re automatically connected to the other party. The caller ID shows the virtual number, masking real numbers from both sides.

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Prerequisites

To use Number Masking:
  1. Plivo account - Sign up with your work email if you don’t have one
  2. Voice-enabled phone numbers - Rent numbers from the Numbers page or via the Numbers API

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Click-to-Call Scenario

In a click-to-call flow:
  1. User taps a call button in your app
  2. Your app displays the virtual phone number
  3. User dials the virtual number
  4. Plivo connects them to the other party
  5. Both parties see only the virtual number as caller ID
Testing: From the first party phone, dial the virtual number. The second party phone should ring with the virtual number as caller ID. Try calling from the second party phone as well. Calls from unregistered numbers won’t connect (unless PIN authentication is enabled).

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Request-a-Call Scenario

In a request-a-call (or “call me”) flow:
  1. User clicks a “Call Me” button and provides their phone number
  2. Plivo calls that number (first party)
  3. When answered, Plivo calls the second party
  4. Both calls are bridged together
  5. Both parties see the virtual number as caller ID
This scenario is useful when:
  • Customers are roaming and can’t make outbound calls
  • You want to absorb call costs rather than having customers pay
Testing: Click the Call Me button and provide a phone number. Plivo should call that number showing the virtual number as caller ID. When you answer, the second party’s phone should ring with the same virtual number displayed.

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Next Steps