Microservices Development & Leadership: Co-led the development of Spring Boot microservices, owning and engineering key backend services while collaborating cross-functionally for Agile feature delivery. Performance Optimization & Scalability: Engineered solutions like multi-threaded wallet transfers with 1-second response times, automated reconciliation pipelines using PostgreSQL and AWS Lambda, and optimized APIs, cutting response times by 33%.Security & Compliance: Strengthened application security through JWT enhancements, OAuth2 integration, encryption using RSA and AES, and secure partner API integrations (PhonePe, VKYC) with PII data encryption.API Integration & Reliability: Integrated 15+ API endpoints, improved modularity through Spring AOP and JPA events, and developed CI/CD pipelines reducing deployment time. Leveraged TDD, Swagger, and rate limiting for robust and secure API management.Rewards & User Engagement: Developed a low-latency reward microservice that increased active users, employed AWS SQS for real-time event publishing, and used CloudFront for image distribution. Enhanced user engagement with dynamic reward modules and Firebase notifications for cashback incentives.