We are seeking a highly motivated and experienced Senior .NET Developer with J2EE platform awareness / contribution with 5–8 years of professional experience to join our team. In this role, you will be a key contributor to a strategic application modernization initiative, transforming a legacy enterprise application into a modern, cloud‑native, microservices‑based platform.

Beyond the initial modernization effort, this pivotal role involves long‑term ownership of the application, including continuous development, system improvements, and feature enhancements in the post‑modernization phase. The successful candidate will operate as a senior owner of a mission‑critical production system, ensuring its stability, performance, scalability, and ongoing evolution to meet future business needs.

The role primarily focuses on building a hybrid microservices platform leveraging a .NET Core backend, a modern HTML5 single‑page application frontend, and an integrated Python‑based service for advanced computation and analytics.

In addition, this role requires a strong willingness to learn, adopt, and contribute to applications built using J2EE technologies as part of the organization’s broader and evolving technology ecosystem. The successful candidate should be open to working across both .NET and J2EE platforms as business needs evolve, supporting cross‑platform collaboration and potential future transition initiatives.

You will collaborate closely with cross‑functional teams to deliver high‑quality, scalable, and resilient solutions while actively participating across all stages of the Software Development Life Cycle (SDLC) and Agile development processes.

Key Responsibilities

Application Modernization & Development

• Design, develop, test, and deploy robust, scalable, and resilient microservices using C#, ASP.NET Core, and .NET technologies.
• Write clean, efficient, well‑documented, and maintainable code that adheres to industry best practices and coding standards.
• Contribute to the development of a modern Single‑Page Application (SPA) frontend using frameworks such as Angular or React.

Post‑Modernization Ownership & Continuous Improvement

• Lead the ongoing enhancement and evolution of the application after the modernization phase.
• Take ownership of the application’s lifecycle, contribute to roadmap planning, and drive improvements aligned with future business requirements.
• Identify opportunities for performance optimization, refactoring, and technical debt reduction.
• Contribute to the continuous improvement of development processes, tooling, and engineering practices.

Cross‑Technology Collaboration

• Work closely with teams developing services in other languages, including Python, to ensure seamless API‑first integration and end‑to‑end functionality for analytics and AI/ML use cases.
• Collaborate effectively within a multi‑technology environment, supporting interoperability across different platforms.

Collaboration & Code Quality

• Participate actively in code reviews, ensuring high code quality, performance, and maintainability.
• Foster a collaborative engineering culture through mentoring, knowledge sharing, and technical guidance.

API Integration

• Integrate third‑party APIs, internal services, and enterprise systems (including Python‑based computation services).
• Apply strong API design principles, including versioning, security, performance, and reliability within a microservices ecosystem.

Production Support & Troubleshooting

• Provide L3 / developer‑level production support, diagnosing and resolving issues in a timely and effective manner.
• Ensure operational stability, system reliability, and minimal downtime.
• Support incident analysis, root‑cause investigation, and long‑term corrective actions.

Technical Documentation

• Create and maintain comprehensive technical documentation covering code, APIs, architecture, and operational aspects.
• Facilitate knowledge transfer and support onboarding of new team members.

Full SDLC & Agile Participation

• Participate actively in all phases of the SDLC, including requirements analysis, design, development, testing, deployment, and maintenance.
• Engage in Agile ceremonies such as sprint planning, daily stand‑ups, reviews, and retrospectives.

Required Skills and Experience

• 5–8 years of professional experience as a .NET Developer, with experience in a senior or lead contributor capacity.
• Strong proficiency in C#, ASP.NET, .NET Core / .NET, and related technologies.
• Proven experience designing and building applications using a microservices architecture.
• Experience with front‑end technologies such as HTML, CSS, JavaScript, and SPA frameworks like Angular or React.
• Solid understanding of object‑oriented programming principles and design patterns.
• Experience with relational databases such as SQL Server, MySQL, or Oracle; experience with managed DBaaS solutions is a plus.
• Experience with unit testing frameworks such as NUnit or xUnit.
• Hands‑on experience with Git or similar version control systems.
• Experience working in Agile / Scrum development environments.
• Exposure to CI/CD pipelines and automated deployment tools.
• Familiarity with Python for data computation or experience integrating with Python‑based services is a strong plus.
• Willingness to learn, adopt, and work on J2EE / Java‑based applications as required; prior exposure to Java or J2EE is an advantage.
• Knowledge of containerization technologies (Docker, Kubernetes) and cloud platforms is an advantage.
• Strong problem‑solving, analytical, and debugging skills.
• Excellent communication, collaboration, and stakeholder‑engagement abilities.

Technical Skills Summary

• Languages: C#, JavaScript
• Frameworks / Platforms: .NET Framework, ASP.NET, .NET Core / .NET, Angular / React (or similar)
• Architectures: Microservices, API‑first design
• Web Technologies: HTML, CSS
• Databases: SQL Server, MySQL, Oracle (including managed DBaaS solutions)
• Tools: Visual Studio, Git
• Testing: NUnit, xUnit (or similar)
• CI/CD: TeamCity, uDeploy, Jenkins, GitLab CI (or similar)

Additional Skills (Pluses):

• Python
• AI/ML integration concepts
• Cloud platforms
• Containerization (Docker, Kubernetes)
• Exposure to or interest in Java / J2EE technologies

Education

• Bachelor’s degree / University degree in Computer Science or a related field.

This role requires a strong willingness to learn, adopt, and contribute to applications built using J2EE technologies as part of the organization’s broader and evolving technology ecosystem. The successful candidate should be open to working across both .NET and J2EE platforms as business needs evolve, supporting cross‑platform collaboration and potential future transition initiatives. Willingness to learn, adopt, and work on J2EE / Java‑based applications as required; prior exposure to Java or J2EE is an advantage.

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Job Family Group:

Technology

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Job Family:

Applications Development

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Time Type:

Full time

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Most Relevant Skills

Please see the requirements listed above.

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Other Relevant Skills

For complementary skills, please see above and/or contact the recruiter.

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Citi is an equal opportunity employer, and qualified candidates will receive consideration without regard to their race, color, religion, sex, sexual orientation, gender identity, national origin, disability, status as a protected veteran, or any other characteristic protected by law.

 

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