Twilio purchased phone numbers can not be registered in the United State’s CNAM Caller ID database. Because of this limitation, most outbound calls from Twilio will display a caller ID composed of the Twilio phone number or a verified phone number used to make the call. In either of these situations, we will use the E.164 formatted phone number in the From parameterof your API request or the callerId attribute of your <Dial> verb.

There are, however, two exceptions. Here are the details:

Custom Text Outbound Caller ID with a Verified Phone Number

A non-Twilio phone number (landline, office phone, etc.) with an existing Caller ID entry can be used to place calls from Twilio once the number has been verified on your account. Outbound calls from Twilio using this verified number should be indistinguishable from calls placed normally from this line.

To place calls using this method, simply use the verified phone number in E.164 formatting in your call request code.

Please note that users who receive a call from your verified phone number and then try calling you back will be connected to the verified non-Twilio number.

International Outbound Caller ID

Standard E.164 formatted caller IDs may not be rendered properly when a call is made across international borders. For full details, please see our article on International Caller ID.

Caller ID for Incoming Calls

Most calls coming in to your Twilio number will display the callers E.164 phone number as the caller ID.

• Some calls may have the Caller ID altered, or display a restricted number code. For more details, please see our article for Caller IDs of Incoming Calls are Incorrect.

• Twilio offers a Caller Name Lookup feature that enables automatic CNAM lookups for incoming calls from US phone numbers. This feature can be enabled via the Phone Numbers page in Console, or by updating the VoiceCallerIdLookup Property for the IncomingPhoneNumbers instance API resource. This feature is available on Elastic SIP Trunks, as well.

• We also offer a number of Caller ID add-ons from multiple providers. These can be found in the Twilio Marketplace in Console.