Looking for Full-Stack Developer for Hybrid Voucher & Digital Wallet Platform Project Description: We are building a scalable, secure micro-change system that converts cash into digital vouchers and a spendable balance. The platform will use WhatsApp and USSD as primary user interfaces, integrated with third-party services for redemption (e.g., electricity, airtime, groceries). Key Requirements: Develop a multi-interface system: a WhatsApp Bot, a USSD interface, a Merchant Web Dashboard, and an Admin Dashboard. Build core backend services: a Voucher Engine for generating/tracking single-use codes, a Spend Balance Aggregator, and a Notification Service. Integrate multiple third-party Partner APIs for real-time redemption (airtime, utilities, etc.). Implement a secure, relational database (PostgreSQL/MySQL) with data encryption and audit logging. Architect the system using a microservices approach (Docker/Kubernetes) with an API Gateway, caching (Redis), and async queues (RabbitMQ/Kafka). Incorporate robust fraud detection, rate limiting, and secure authentication (JWT/OAuth 2.0). Required Skills: Backend Development (Node.js/Python/Java) Microservices & API Gateway Design Database Design & Management (PostgreSQL/MySQL) WhatsApp Business API & USSD Integration Third-Party API Integration DevOps & Cloud Deployment (AWS/GCP/Azure, Docker, Kubernetes) Security & Fraud Detection Implementation Please provide examples of previous similar projects, especially those involving financial transactions, voucher systems, or chatbot/USSD integrations.