Payment Gateway Site Development

I need a full-featured payment gateway website that works the way kotanipay.com and boodil.com do, yet carries a fresh visual identity of its own. The core objective is functionality: merchants must be able to sign up, generate payment links or embed a checkout widget, and track transactions in real time.

To keep the build focused, here is what I expect as tangible deliverables:
• Responsive public site plus merchant dashboard (user management, transaction history, basic analytics)
• Secure API endpoints so external stores or apps can initiate and verify payments
• Admin panel for me to approve merchants, manage fees, and monitor system health
• Integration layer ready for popular processors (PayPal, Stripe, Square or equivalents) with the flexibility to swap in additional rails later
• Clear documentation covering API, onboarding flow, and day-to-day operation

Clean code, industry-standard security practices (SSL, tokenization, PCI-aware development) and smooth performance are non-negotiable acceptance criteria. If you have built gateways or complex fintech products before, please share a live link or demo credentials so I can see them in action.