Order approval referred to as A web service, have an independent API and the background of the control panel, their work is to analyze the buyers payment it will put the order into safe shipment, need human review and then make A decision whether to deliver goods and dangerous unsafe order 3 classes to give I usually order review time for up to 30 minutes and then I have seen in their landing page will review the results

Automatic email web service (B, have an independent API functions and background control panel, receive a payment instruction by E-mail, please note that the actual B is a fool software whether order security send email after payment

Demand is customer payment is received email

I am going to put two service how to implement seamless integration
Note: this is my point,
1 how can let party B sent automatically from A security order,
2 need artificial audit, if can confirm email customer service staff need to be in the background (I don't know which background is A or B or how do I get entangled with A button operation tell party B, if not safe audit after confirmation of order is not sent,
3 unsafe orders, not sending email

The two web services, respectively, I find a representative for your reference
A http://www.signifyd.com/
B: http://www.payloadz.com