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At Citi, we believe in the power of engineering to drive success and foster a culture where innovation, collaboration, and professional growth thrive. Join Citi's Oasys Financial team as a Senior Java Developer and take a pivotal role in a landmark modernization project. Oasys is Citi’s core sub-ledger system for the Over-the-Counter (OTC) business, processing millions of trades daily. We are embarking on a major strategic initiative to transform this key platform, moving it from a legacy system built on shell scripts into a state-of-the-art architecture based on modern Java microservices. We are seeking a highly skilled and motivated technical leader to drive the design, development, and delivery of our next-generation financial accounting systems, ensuring they meet the highest standards of scalability, performance, and security.
Job Responsibility
Lead the re-architecture of our legacy financial ledger, migrating complex business logic from shell scripts and stored procedures into a modern, event-driven platform built on Java microservices
Design, develop, and implement high-performance, scalable, and secure Java applications that will form the new backbone of our financial systems
Write clean, well-documented, and thoroughly testable Java code. Act as a champion for software engineering best practices, including Object-Oriented Design, SOLID principles, and Test-Driven Development (TDD)
Collaborate closely with database teams to design and implement strategies for data integration and migration as part of the transition to the new Java architecture
Act as a key technical expert, troubleshooting and resolving complex issues that arise during system migration, modernization, and in production
Conduct rigorous code reviews, mentor junior developers, and contribute to the continuous improvement of team standards and development processes
Work in close partnership with product managers, business analysts, and other global teams to ensure technical solutions are perfectly aligned with evolving business requirements
Requirements
8+ years of hands-on professional experience in designing and building robust, scalable, and maintainable server-side applications using Java
Strong expertise in Object-Oriented Design, data structures, design patterns, and concurrency
5+ years of significant experience with SQL databases, demonstrating proficiency in writing complex queries and optimizing database performance
Strong command of the Unix/Linux environment, including familiarity with system-level operations and administration
Bachelor’s degree in Computer Science, Engineering, or a related field
Nice to have
Proven experience in migrating complex, large-scale legacy systems (particularly those heavily reliant on shell scripting and monolithic databases) to modern, cloud-native microservices architectures
Deep familiarity with modern Java frameworks (e.g., Spring Boot), microservices architecture, and containerization platforms (e.g., Docker, OpenShift)
Experience using AI-powered development tools (e.g., GitHub Copilot, Claude, Devin) to accelerate development and improve code quality
Hands-on experience with enterprise-level SQL databases such as MSSQL
Proficiency in shell scripting
A solid understanding of the financial accounting domain, including concepts like posting, calculations, and sub-ledger processes
What we offer
Impact: Take a leadership role in a high-visibility modernization project that will directly shape the future of Citi's global financial operations
Challenge: Solve unique and rewarding technical challenges while dismantling a legacy system and building a cutting-edge platform from the ground up
Culture: Be part of a world-class engineering team in a dynamic, collaborative, and supportive environment that encourages innovation and continuous learning
Growth: Access Citi’s extensive professional development resources and enjoy clear pathways for career advancement within a leading global financial institution