Usman Firdous

Lead Java Developer @Mastercard

Manhattan, NY, US

Developed and maintained scalable, high-performance Java Spring Boot microservices for Mastercard’s payment processing systems using REST APIs.•Designed and implemented resilient services leveraging Circuit Breaker patterns (using Resilience4j) to ensure fault tolerance and improve availability.•Maintained clean code practices and enforced coding standards through SonarQube integration with Bitbucket pipelines.•Led the implementation of CI/CD pipelines using Bitbucket, Jenkins, and Nexus, enabling faster and safer deployments across multiple environments.•Refactored legacy modules into microservices by applying Domain-Driven Design and ensuring proper service boundaries.•Implemented functional test suites to validate business logic and data consistency across distributed services.•Integrated OAuth2.0 and JWT-based authentication to secure internal APIs.•Optimized system throughput and reduced latency by applying connection pooling, thread tuning, and caching strategies.•Participated in Agile ceremonies, including sprint planning, retrospectives, and demos, contributing to continuous delivery practices.•Mentored junior developers on best practices in Java, Spring Boot, and test-driven development (TDD).Supported production deployments and resolved critical issues under tight SLAs, improving system uptime and client satisfaction