• Built and maintained a Payment Orchestration Service using Java 17 and Spring Boot, enabling reliable transaction processing across multiple payment providers in a multi-region AWS environment (EC2, ECS, RDS, CloudWatch).
• Developed reactive REST APIs with Spring WebFlux to handle asynchronous payment flows and third-party callbacks, significantly improving system responsiveness and reducing peak-time latency from 320ms to 85ms.
• Designed a Kafka-based retry and recovery mechanism (topics, consumer groups, DLQ) to handle failed transactions, strengthening fault tolerance and reducing transaction loss in production environments.
• Contributed to the checkout experience by building a React 18 and TypeScript-based UI, applying performance optimizations such as lazy loading and code splitting to improve load times and overall user experience.
• Integrated secure payment capabilities including Braintree Vault tokenization and 3D Secure 2.0, ensuring compliance with PCIDSS standards and strengthening fraud prevention measures.
• Implemented secure authentication and authorization using OAuth 2.0 and OpenID Connect with Spring Security, enforcing fine grained access control for APIs interacting with 12+ downstream partner services via PayPal’s internal Identity Provider.
• Enabled controlled feature rollouts and experimentation using LaunchDarkly, supporting A/B testing initiatives that contributed to an 8.3% increase in checkout completion rate.
• Strengthened development workflows by building CI/CD pipelines with Jenkins and GitHub Actions, incorporating automated testing (JUnit 5, Mockito, TestContainers) to improve release reliability and reduce deployment time from 3 days to 4 hours.
