php shopping carts...question about the checkout URL

Hello,

I've been looking into 3rd party PHP shopping carts that you can buy/rent to use on an ecommerce site.

During checkout, every cart I've seen bumps the buyer to a 3rd party payment URL. Is there a way to prevent this?

For example, say you had a site called www.sneakersforsale.com. When you go to the checkout page to enter your credit card information, the cart will flip you to a site like:
www.paypal.com/user=?php=get=g!=133543

What can I do structurally so the checkout process stays in the store's actual site domain? Meaning, the credit card page will look something like:
http://www.sneakersforsale.com/checkout/php?=143&get=post

or maybe like a subdomain:
http://checkout.sneakersforsale.com/php?=x33=4df&=get

Is this a matter of getting a merchant account like authorize.net, or is it something else?

Thanks for any ideas.

P.S. (the above examples are not intended to be correct php code. i don't know how to code php very well, so I'm just putting fake code in there to show what I'm talking about)

For starters, what you posted is not PHP at all, it's simply switches for POST variables inside the URL.

But to answer your question, you could use iframes to house the checkout page, the address bar would stay the same, but the page would still be 3rd party.

Or, you can do like you suggested and purchase a merchant account. Thats all PayPal, 2checkout, etc.. are. They are shopping carts and merchant accounts integrated into one.

I'm actually writing one of these shopping cart systems as we speak.

Paypal and Google Checkout style payment processing kinda requires you to redirect to a new page. I don't believe they allow you to iframe them, but I could be wrong.

Proper merchant accounts and card processing providers like SagePay will allow you to keep the customer on your site at all times, bar one: A lot of cards require you to redirect the customer to a bank owned website for additional authorisation, though I believe you can do that in an iframe.

You can disable 3D Secure, btw, but then the fraud risk is your own. You don't want that.

Thanks,

that's great information.

I was getting the idea that having a proper merchant account set up would be a requirement. I wasn't developing the idea that an iframe was part of the scene. But after your posts I see that an iframe is important.