What are the accepted phone number formats for Voice?

Question

How can I add a user phone number in Zendesk? Can extensions be added for direct lines?

Answer

Yes, you can add extensions for direct lines. Phone services for Zendesk Voice (formerly Talk) route through Twilio. Zendesk systems utilize Twilio guidelines to format phone numbers. The Twilio documentation recommends that you format phone numbers with the internationally standardized E.164 format. E.164 numbers can have a maximum of 15 digits and are usually written as [+][country code][subscriber number including area code].

An example of a United States number in the E.164 format is +16175551212.

To add an extension to a user phone number, append an x and the extension to the end of the phone number. An example is +14155551212x123 as shown in the image.

If you have the Validate user phone numbers setting turned on in your account, phone numbers added to user profiles without this format fail to save to user profiles. For more information, see Managing end-user settings.

When you turn off the Validate user phone numbers setting, the system doesn't apply formatting to the number you add in the Phone field for a user, even when you set that number as a direct line. This means the system doesn't automatically add the characters +1 or +. The system doesn't remove special characters such as () or additional spaces in the number.

Important: To automatically associate calls with the correct user profile, the system relies on the number in the E.164 format. For example, if a user has the phone number +1 (415)-555-1212 in the profile, it doesn't match +14155551212. The system treats these numbers as separate entities. The best practice is to merge end-user profiles related to the same customer with different number format variations.