World Pay (or rather RBS World Pay now) is a well know online payment processing service provider. A lot of e-commerce websites use their services to provide their customers a secure way to make payment online for the goods/services they purchase.
RBS World Pay provide their own API for payment processing which store owners can integrate with their website and allow online payment transactions. Its quite easy to integrate with your website. You can embed the following piece of form code in your website and start accepting payments from your customers.
<form action="https://select.worldpay.com/wcc/purchase" method="post" name="form1"> <input type="hidden" name="instId" value="<your_installation_id_here>"> <input type="hidden" name="cartId" value="<shopping_cart_or_order_id_here>"> <input type="hidden" name="currency" value="<3_digit_currency_code_here>"> <input type="hidden" name="desc" value="<shopping_cart_items_here>"> <input type="hidden" name="testMode" value="100"> <input type="hidden" name="amount" value="<order_total_here>"> </form>
The above is basically a simple form code of passing the values of the customer shopping cart to World Pay. You can also add custom form fields which can be passed onto World Pay. The custom form fields are only useful in the case when you need some information to be returned from World Pay instead of storing them in cookies or session. The value of 100 against testMode denotes that the transaction is not live. If you need to set it live then you will have to set testMode to 0.
Once the above form is posted to World Pay and there is no problem with the data then the checkout process starts on World Pay website.
Hope the above helped.