Updating a contact through Zapier or API doesn't overwrite all empty fields

[CMCDTLA]

From the API documentation: Constant Contact v3 API

"When updating any resource using PUT, all properties are updated, overwriting all previous values."

Also in Zapier 

From Zapier

Would be great if only selected properties are updated, leaving the others intact.

[John__B]

Hello CMCDTLA,

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.

Thanks so much for your feedback. It has been submitted for review and consideration by our engineering team. Your feedback and experience with this request is essential to improving our product, so thank you for reaching out to us regarding this matter.

I just wanted to note that all properties being updated/overwritten with PUT requests to the /contacts endpoint does not apply to contact subresources such as custom fields, list memberships, phone numbers, street addresses, taggings or notes.

Please let us know if you have any questions!

Regards,