Email Validation

0 Votes
Is there a comprehensive list of the validation that Constant Contact performs for email addresses? We are using the API and would like to perform our own validation before making API calls so that bad data is not sent to the API. However, we have been unable to find a list of what CC considers to be an invalid email address.
0 Votes



Thank you for reaching out to Constant Contact API Developer Support. My team is here to assist outside software developers with questions about building into Constant Contact's API.


We don’t currently have full documentation for the criteria that Constant Contact uses to validate imported email addresses, however, I will be opening a feature request for this documentation to be made available. There are some basic checks that you could use for validation on your end before importing contacts to Constant Contact. This would include things like ensuring that there are no spaces in the email address or unsupported characters such as commas or brackets. You would also want to ensure that each address contains an “@” symbol followed by a complete domain name. 


I would also note that when importing contacts via API, sometimes an invalid email address error may be returned when our system has detected signup abuse. Signup abuse occurs when more than 5 attempts are made by an email address to subscribe to Constant Contact newsletters or update its profile within a 24 hour period. When signup abuse is detected, the address is flagged for 48 hours and won’t be able to be added to Constant Contact accounts for that period of time.


Please have a look and let us know if you have any other questions!



John B.
API Support Specialist
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