If you want to get more details about Customer, Orders, Invoice and Payment of Shopping cart transaction, you can use this API. If you configured success url for shopping cart, then a unique ID will be sent in params to success url (check here for more details). You can use that ID as params to this api.
Initiate the Verify Cart Request
GET /rest/shoppingCart/verify/<GUID_OBTAINED_FROM_SUCCESS_URL>
Example: /rest/shoppingCart/verify/QzoxMjN8TzoyMTUyfEk6Mjk0MnxQOjE4ODE=
Sample XML response:
<cartSignup>
<customer>
<companyName>Tuscon Pharma and Labs</companyName>
<firstName>John</firstName>
<lastName>Doe</lastName>
<extCustomerRef>2441</extCustomerRef>
<email>johndoe@tusconpharma.com</email>
<phone>555-555-5555</phone>
<login>johndoe@tusconpharma.com</login>
<address>
<street1>SUITE 5A-1204</street1>
<street2>799 E DRAGRAM</street2>
<city>TUCSON</city>
<state>AZ</state>
<zipcode>85705</zipcode>
<country>United States</country>
</address>
</customer>
<subscriptionOrders>
<subscriptionOrder>
<orderNumber>2152</orderNumber>
<contractCode>ANTI-VIRUS-MONTHLY</contractCode>
<quantity>1.0</quantity>
<status>Active</status>
<startDate>2016-10-18</startDate>
<invoiceText>Anti virus Monthly</invoiceText>
<couponCode></couponCode>
</subscriptionOrder>
</subscriptionOrders>
<invoices>
<invoice>
<invoiceNumber>2942</invoiceNumber>
<invoiceDate>2016-10-18</invoiceDate>
<invoiceAmount>1015.95</invoiceAmount>
</invoice>
</invoices>
<payment>
<paymentAmount>1015.95</paymentAmount>
<paymentStatus>Paid</paymentStatus>
<paymentApprovalCode>XYZ512.4587117433755</paymentApprovalCode>
<creditCard>
<cardType>Mastercard</cardType>
<cardholderName>John Doe</cardholderName>
<expiry>2020-10-31</expiry>
</creditCard>
</payment>
</cartSignup>