Custom E-commerce Payment Gateway

I need a seasoned developer to build a payment gateway entirely from scratch something like checkout.com . The core engine must process real-time sales, captures, refunds, and voids while meeting strict PCI-DSS requirements and passing 3-D Secure 2.0 checks... (Budget: $30 - $250 USD, Jobs: API Development, eCommerce, Payment Gateway Integration, PayPal API, PCI Compliance, PHP, RESTful API, XML)