[Integration] Clarification on best endpoint for subscription forms

Hi,

We are currently integrating our App with Constant Contact and are evaluating the appropriate endpoint for subscription forms. Could you please advise on whether we should use the createContact(v3/contacts) or createOrUpdateContact(v3/contacts/sign_up_form) endpoint?

From our understanding, both methods seem to support double opt-in, depending on account settings. While the createOrUpdateContact(v3/contacts/sign_up_form) endpoint appears semantically suitable, our tests indicate that it can update contact fields without confirmation. Is this expected behavior?

Thank you for your assistance.