Hi Denis,
all the payment processors use a web api, and any web api they offer will be easy to use from any client, including VFP. So look for the best combination of no monthly fee and low rate. Stripe (stripe.com) is usually the best for normal-volume businesses, from my explorations.
Hank
>Once again It looks like I didn't explain what I wanted well enough. Sorry English not my native language.
>
>I meant a service like
>
www.authorize.net>
>So far it looks like authorize.net is the only one where I could get VFP source code samples.
>
>Do you know other enterprises that would offer that kind of service?
>
>
>
>>Adding to John's recommendation: if it's just for you, PayPal has invoicing available for business accounts. As, of course, does Quickbooks Pro version.
>>
>>>I need to do on-line invoicing. How do I do it. Is it possible to do it only with VFP code or are third party tools absolutely necessary?
>>>
>>>Any source code to share?
>>>
>>>Any tool makers to recommend?
>>>
>>>What else that I should know?