This HTTP POST link is used to copy earliest future billing (renewal) date from user’s record into desired Infusionsoft field/custom field for that specific user.
The Copy Next Billing Date HTTP POST function is compatible with Legacy HTTP POSTs, Actionsets, and Campaign Builder.
The Copy Next Billing Date HTTP POST takes the following parameters
auth_key: Your Memberium HTTP POST authentication key. You can find a list of your valid i2SDK authentication keys in your i2SDK plugin.
destfield (required): The contact field where to store the next billing date
id (required): Infusionsoft contact id