Job Summary 

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. 

Key Responsibilities 

As a Senior Developer, you will be a technical leader at the heart of this transformation. Your duties will include: 

• Re-Architect and Modernize: 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. 

• Hands-On Development: Design, develop, and implement high-performance, scalable, and secure Java applications that will form the new backbone of our financial systems. 

• Champion Code Quality: 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). 

• Database Integration: 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. 

• Problem Solving: Act as a key technical expert, troubleshooting and resolving complex issues that arise during system migration, modernization, and in production. 

• Mentorship and Leadership: Conduct rigorous code reviews, mentor junior developers, and contribute to the continuous improvement of team standards and development processes. 

• Cross-Functional Collaboration: Work in close partnership with product managers, business analysts, and other global teams to ensure technical solutions are perfectly aligned with evolving business requirements. 

Qualifications 

Required: 

• Experience: 8+ years of hands-on professional experience in designing and building robust, scalable, and maintainable server-side applications using Java. 

• Technical Depth: Strong expertise in Object-Oriented Design, data structures, design patterns, and concurrency. 

• Database Skills: 5+ years of significant experience with SQL databases, demonstrating proficiency in writing complex queries and optimizing database performance. 

• Operating Systems: Strong command of the Unix/Linux environment, including familiarity with system-level operations and administration. 

• Education: Bachelor’s degree in Computer Science, Engineering, or a related field. 

Preferred (Highly Desirable): 

• Legacy Modernization: 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. 

• Modern Technologies: Deep familiarity with modern Java frameworks (e.g., Spring Boot), microservices architecture, and containerization platforms (e.g., Docker, OpenShift). 

• AI-Assisted Development: Experience using AI-powered development tools (e.g., GitHub Copilot, Claude, Devin) to accelerate development and improve code quality. 

• Database Systems: Hands-on experience with enterprise-level SQL databases such as MSSQL. 

• Scripting: Proficiency in shell scripting, which will be essential for understanding and migrating the legacy system. 

• Domain Knowledge: A solid understanding of the financial accounting domain, including concepts like posting, calculations, and sub-ledger processes. 

Why Join Us? 

• 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.