Built a secure, full-stack online banking system enabling 24/7 account access, fund transfers, bill payments, and transaction management across web and mobile platforms. Designed RESTful APIs, optimized database queries, and implemented real-time transaction updates to ensure high performance, scalability, and seamless user experience. Implemented advanced security features including JWT authentication, multi-factor verification, encrypted data transmission (SSL/TLS), role-based access control, and fraud-prevention logic. Architected ACID-compliant transaction handling, audit logs, and production-ready deployment with Nginx and process management for high availability.