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Required EMail format when using API?

Regular Participant

Required EMail format when using API?

What are the requirements for valid email formats when adding/updating Contacts via the .NET API?   The most recent addressing on this issue that I found is in this thread:



that thread links to this FAQ entry on email formatting:



I've been using a well tested RegEx expression to validate all our email address strings prior to attempting to add contacts to lists via the .NET API.      Still, I get exceptions triggered by 'bad email format'.  When I examine the email that triggered the exception, it appears to be within the guidelines laid out in the FAQ. 


Example of Email string triggering an exception:    X0Znuaavwebrw0330@marauder.millersville

I realize that email address IS bogus....but I do not see what part of it fails the guidelines in the FAQ doc.


So, are there more recent guidelines some where?  Or maybe an algorithm that never fails that somebody wants to share?   Thank you.




Something extra to note is that our validator will pass only common, simple TLDs.  The email example you provided probably did not pass validation because there is no TLD called "millersville".


Hope that answers your questions.




Andrew B.

Constant Contact

API Support

I am running into the same issue.  I have tried pushing emails with a .xxx tld and it doesn't work. I have also been referring to the  ICANN list of tlds and some of those do not work either. Do you have a list of TLDs that CC considers valid? Thanks!

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