For the Constant Contact API POST endpoint "/contacts/sign_up_form" to create or update a Contact, there does not appear to be any way to add/update Tags assigned to a Contact record in that case, as there is with the "/contacts" POST endpoint to create a new Contact. Are there any plans to add support for Tags at the "/contacts/sign_up_form" POST endpoint, or could that feature be added to the API please? I realize it would be possible to accomplish this by running a series of multiple API calls using the GET, POST, and PUT methods at the "/contacts" endpoint to find/check and then create/update a Contact with Tags, but it would be much more convenient and less resource-intensive to have Tags included at the "/contacts/sign_up_form" POST endpoint if at all possible.
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.
As you mentioned, there are several different ways that a tag could be added using one or more additional calls, but at this time there is not a way to include the Tag value when making POST calls to the /contacts/sign_up_form endpoint. While no error is returned if the value is included within the request body, the endpoint ignores that data and does not add the tag.
An easy alternative would be to use additional lists, one as the desired mailing list, and one as the placeholder for the tag, and then have the call add the sign-up to both lists.
I was unable to find any information specifying why the Tag value was not included when creating the request body schema for the Sign-up Form endpoint, but have passed along your request to our developers for consideration.
Your feedback and experience with this request is essential to improving our product, so thank you for reaching out to us regarding this matter.
Please have a look and let us know if you have any other questions!