I have opened a profile with Mastercard Payment Gateway Services and now need the REST API at https://bobsal.gateway.mastercard.com/ wired into my system so the new merchant account is fully operational. The goal is straightforward: accept and manage both credit- and debit-card transactions directly through the gateway and expose the usual lifecycle calls—authorise, capture, refund and recurring—so my application can trigger them programmatically. Here is the exact scope I need covered: • Configure the account credentials and generate the live API keys inside the gateway. • Build the server-side integration using the official Mastercard Payment Gateway (MPGS) REST endpoints for – one-time payments, – scheduled / recurring payments, and – refund processing. • Return all mandatory response data (transaction IDs, result codes, risk scores) back to my app in JSON. • Provide a short walkthrough or commented code so I can maintain keys and endpoints later. I’m language-agnostic; PHP, Node, Python or Java are all acceptable as long as the solution is clean, secure (PCI-aware) and easy for me to drop into production. Hand-over is complete when I can run a live card test and see approved, declined and refund scenarios reflected in the gateway dashboard as well as in my application logs.