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Telephone Verification


Telephone verification is the process of calling back a consumer at the phone number they have provided in order to verify the phone is working and the person in possession of the phone is the one placing the order. It is available as a hosted bureau service.

Key considerations when implementing or buying this functionality include:

  • What countries are supported?

  • How does the service handle unanswered calls?

  • Can the session be handled from within your site or do you have to pass off to another outside session?

  • Look into telephone type authentication, TNI.

  • Look into name, address and phone authentication as well.


Telephone Verification works by automatically calling an online end-user's telephone number at the same time the end-user is making a transaction on a website. The user, while on the website, answers the phone and is provided a one-time personal identification number (PIN), the PIN is randomly generated and must be provided by the end-user to confirm possession of the phone. An otherwise anonymous online end-user will be able to confirm that the person who received the phone call and the person who is interacting on the website are the same person.

Telephone Verification works with a 4-step process:

  1. Merchant requests consumer verification

  2. Automated call is generated to the consumer

  3. Consumer inputs the PIN they received on the phone call into the website

  4. Merchant confirms the PIN and the consumer is verified


If the consumer, or end user, cannot verify through the phone you should prompt them to try again with another phone number. If they cannot pass on further attempts you should assume the consumer or end user is high risk.


Typically phone verification is used in manual reviews to do one more verification of a consumer’s address and phone information when AVS is not a full match. But some merchants are using automated telephone verification services to ensure they have a valid phone number for each customer. The process is simple, and while requiring a little more user interaction, it fits easily into the online real time process.

NOTE: This has been a popular technique for businesses that are involved with paying out money.

“Gotchas” with phone verification include:

Don't forget to do simple phone standardization and checking to prevent wasted verification attempts.

If you don't do authentication of a phone number before you verify it, then your verification loses a lot of strength. There are two levels of authentication: phone type and phone to name/address.

This can get expensive if you are doing international business.

This process does require a change to the user experience.

Don't forget to perform other redundant checks to catch unwanted behavior.



Alternative SolutionsArea code mapping, identity authentication, reverse phone lookups.

Building this In-House - N/A

Estimated Cost - Typically this service is offered on a per-transaction basis. This service is usually fairly inexpensive for USA, but the price can vary dramatically based on the countries you do business in.

Sample Vendors - TeleSign, TNSVerify

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