The Ocelot contact list upload feature includes a phone number validation process to ensure most phone number formatting is accepted. 

The validation process will determine that what is being imported as a contact is a valid phone number. The validation process will also ensure that different configurations are formatted into a proper phone number format. Generally, the validation process will ensure that what is being uploaded does not include text characters or any other special characters not recognized.

The contact upload validation process that occurs does not confirm whether the phone number is reachable or a viable cell phone number. It simply determines that the information uploaded is a phone number or appears to be a phone number and can be treated as such. 

The validation process can generally accept numbers uploaded with: 

  • dashes
  • periods
  • parentheses
  • no punctuation

Examples of valid formats include: 

(123) 456-7890







If a phone number is problematic upon contact list upload and is not able to be imported, you will receive an argument validation error. To avoid issues with contacts when uploading, it is recommended that you groom your original list (before importing) by sorting the phone number column from large to small and quickly scrolling through the list. Any problematic numbers should float to the top or bottom where they can be easily eye-balled and fixed.

Note - when you are uploading a contact list and you include an international number, the number will successfully import into the contact list; however, the message will not send. Campaigns/1:1 Texting does not currently support international texting. You will see a delivery failed reason = international number in the campaign analytics after the campaign is launched.

If your CSV includes a header row, when creating a new contact list, be sure to switch the toggle to on (green) to indicate you have a header row. This will ensure the validation process does not try to import your header row as a contact (which will produce argument validation errors). 

After a contact list is successfully imported and the Campaign is launched, messages will either deliver successfully or fail to send. See also: How do I view the message delivery status in campaigns? and How do I prevent my messages from being blocked?