Create your own payment gateway

As of Shopkit v1.1, all payment gateways are defined in a standardized way within the site/plugins/shopkit/gateways folder.

Square, Stripe and PayPal are included. Here’s how to add your own gateway, if you want to give your customers another payment option:

Setting up the folder

Open process.php. This is where your customers will be directed when they click Pay Now. Shopkit will pass along the $txn object so you can use that data.
A process.php should send the transaction data and payment information to the gateway.
Never collect users’ credit card information directly with the Shopkit server. All sensitive details should be handled by the gateway, either directly on their site, or through a SDK provided by them.
Make sure the gateway has a callback URL where it will send the transaction response. This should be /shop/cart/callback/[gatewayname]

In callback.php, verify the charge against the pending order.
callback.php needs to update the transaction text file with 'status' => 'paid', the gateway transaction ID, and any customer details you might have
Make sure you include the order.callback snippet, which updates inventory and sends any required notifications.
If all is good, send the user along to http://example.com/shop/confirm, passing as many variables as you can to autofill the form (txn_id, payer_name, payer_email, payer_address).