Can I send a variable to paypal, and have it post it back to me when payment completes?

Iten_number hidden variable don’t work in my application. But i found that custom hidden field works fine. Just add this field to the form, generated by paypal: <input type="hidden" name="custom" value="YOUR VALUE FROM DB"/>. After, you can read this value to identify, for example, what product have been purchased. (Java code): String custom = request.getParameter("custom");