Call masking is a technology that allows two parties to communicate without revealing their actual phone numbers. Instead, a virtual number is used to protect the privacy of the caller and the receiver. This is similar to the way that Uber or Just Eat allow you to communicate with your driver without the two of you having to share numbers.
Keep your number secure
As a premium user, this feature is active by default. When somebody calls you after scanning your pet's Crumb tag, they'll see a random number, but their call will re-route to the number you've uploaded on your account. They will see something like this, where the number on the blue "Call" button is a random number generated by the app for display purposes only.
If you're testing out your pet profile by having a friend call you, don't be surprised when you see a random number here! If you click the blue button that appears, it will re-direct your call to the number on your account!