How do I maximize the accuracy of API phone validation?
Make sure all phone numbers include the full international format with the country code, such as +1 or +44.
The system ignores special characters such as hyphens, periods, parentheses and spaces and validates the phone numbers correctly.
Remember to include the country code when you pass the phone number to GetResponse. If you don’t, we may not be able to validate the phone number, and it won’t append to your subscriber’s profile.