App Integrations: Payments, WhatsApp, Instagram

My app already runs smoothly on both iOS and Android, but the external services it relies on still need to be wired up. I want every major integration—payments, social, and messaging—implemented end-to-end so users enjoy a seamless experience without ever leaving the app... (Budget: ₹600 - ₹1500 INR, Jobs: API Integration, Instagram API, iOS Development, iPhone, Payment Gateway Integration, PHP)