I have an eCommerce website in PHP that is currently using PayPal Pro for payment processing.
I need to switch gateway processing to AuthorizeNet using their API. A straight forward project for someone that know how to setup AuthoraizeNet API payment. I have a AuthorizeNet sandbox account and credentials.
Since you willbe worrking on the live site this has to be implemented in parallel with the current processor, tested and then just switched over with no down time.