It is the responsibility of the calling party to pass a caller ID to Twilio when making a call into our network. However, this exchange is not standardized, and occasionally you may find that caller IDs are inaccurate or contain non-E.164 number formatting, particularly for calls that cross international borders. Twilio is only able to directly pass through the caller ID that it receives from the calling party, so unfortunately we’re not able to fix inaccuracies.
For outbound calls from your Twilio account, we will pass along the caller ID that is specified to us in your REST API request. From time to time, there are also issues with these caller IDs. If the party you are calling consistently sees an inaccurate caller ID, contact us. While we are not always able to resolve these inconsistencies (due to the recipient carrier), we will investigate to see if there is anything we can do.