There are currently two ways to get a website up and running entering payments into Green! The first way is to create a custom integration using our eCheck API and the second is to use one of our pre-built plugins for an eCommerce Platform. Though they are related, they do not use the same API and each of them has noted differences that you should be aware of when integrating.
The eCheck API is our "bread-and-butter" API as far as functionality and flexibility goes. It contains the highest variety of methods effectively replacing most functionality available in the Green Portal like overriding, cancelling, invoicing, customer list editing, etc. When merchants make custom integrations for their website, this is the API we recommend that they use 99% of the time.
Our pre-built eCommerce plugins however use the eCart API which is a highly stripped down and simplified version of the eCheck functionality. It does NOT allow for overriding Risky checks nor can it handle invoicing, billpays, or any other functionality. Due to this, most of our plugins cannot handle taking Risky checks.
At this point in time, the only integration which does not use the eCart API is the WooCommerce plugin which *can* allow merchants to take Risky checks if they so choose, though the default behavior is to match that of the eCart API.