I want to add a custom tender (attached documentation). The flow would require to fetch all merchant payment tenders on their shopify, magento or woo commerce account and add one custom tender additionally which is attached by calling one API. I would like to develop a plugin which can be installed on magento or woocommerce or shopify server (we can have different plugins for each platform).
P.S. There is also a refund API for transaction reversal if the case is needed.