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.
I’m not sure which Zapier integration you’re using to import contact data from your online form, but our V3 API’s Bulk Activities endpoints for importing large numbers of contacts do support birthday_month and birthday_day values. Below I’m including documentation on these endpoints.
You’re welcome to share this documentation with Zapier and see if these fields could be added to the integration you’re using. If they have any questions or concerns, they can reach out to us directly at firstname.lastname@example.org .
Aside from using or developing another integration which does support these fields, the best method for updating the Birthday for large numbers of contacts would be importing via a spreadsheet.
Please note that Zapier is a 3rd party product and not built or supported by Constant Contact, so we are limited in the support we can provide, but will try to answer any questions to the best of our ability as they pertain to Constant Contact’s API endpoints and functionality.
Please have a look and let us know if you have any other questions!
... View more