I had a requirement in one my latest project to add a product to woocommerce cart when submitting a Gravity form. ie an user customized product. Here it is how I achieved that.
Recently my client asked me to write code for adding ActiveCampaign subscriber list when submitting a Gravity form. There is addons available for most of the mail campaign. But not for ActiveCampaign. Here is how I achived that, though it seems bit complicated.