Official comment
OptimizePress has an article on using their API integration with ONTRAPORT at this link: https://optimizepress.zendesk.com/hc/en-us/articles/204078693-Integrating-with-Ontraport-
The example given adds a new opt in to a Sequence in ONTRAPORT. OptimizePress will provide support for this integration (there is a button on that page to contact their Support department).
Comment actions