This add-on for Gravity Forms adds each form submission to Constant Contact as a new contact, so your mailing list builds automatically. It requires an SSL certificate.

Map any form field to a Constant Contact custom field, and choose the list new subscribers join. The built-in Consent field captures permission before anyone is added to your list.

Conditional logic decides when submissions are sent: only contacts who opt in, only qualified leads, and nothing that fails your criteria.