Integrate Youpi-PG Payment Gateway

My custom website needs a full Youpi-PG payment gateway integration, covering everything from secure key setup to a smooth checkout flow. This includes connecting to Youpi-PG’s APIs, handling all success-and-failure callbacks, and making sure transactions post correctly on both the site and the merchant dashboard.

Key deliverables
• Gateway configured with live and test credentials
• Front-end payment form that tokenizes card data and submits through Youpi-PG
• Server-side code that verifies signatures, logs responses, and updates order status
• End-to-end test proving a successful transaction and a declined scenario
• A short implementation guide so I can maintain keys or toggle sandbox/live mode later

Provide clean, well-documented code that meets basic PCI best practices, uses HTTPS for all calls, and does not expose private keys in the repository. I will share the current tech stack and server access once we start.