Senior Java Backend Engineer

• Build and deploy asynchronous, event-driven microservices in Java, ensuring high availability and performance at scale.
• Design reactive backend services using Spring Web Flux, Project Reactor, and RxJava to meet demanding throughput and latency requirements.
• Develop and maintain real-time event streaming pipelines using Apache Kafka to power data-driven features across the platform.
• Engineer search and analytics capabilities using Elasticsearch to surface fast, accurate insights from large data sets.
• Architect and optimise data persistence solutions in MongoDB, ensuring efficient storage and retrieval of application data.
• Champion code quality by leading test-driven development practices, writing comprehensive JUnit test suites, and guiding teams through rigorous code reviews.
• Mentor mid-level engineers and analysts, establishing coding standards and sharing knowledge to strengthen overall team capability.
• Partner with product, infrastructure, and architecture teams to deliver new features and define system enhancements aligned to business goals.

• 6-10 years of backend software development experience, with a demonstrable focus on building and scaling Java applications.
• Deep proficiency in Java (8+), including functional programming with Lambdas and reactive paradigms using Spring Web Flux, Project Reactor, or RxJava.
• Hands‑on experience building and integrating event streaming systems with Apache Kafka.
• Solid command of MongoDB for No
  
  SQL data modelling and Elasticsearch for search and analytics implementations.
• Expert‑level application of test‑driven development using JUnit, with strong discipline around unit testing and code coverage.
• Proficiency in Git‑based collaborative workflows, including pull requests, code reviews, and branching strategies such as Git Flow.
• Familiarity with CI/CD pipeline design to support automated testing and continuous deployment processes.

• Experience containerising and orchestrating applications using Docker and Kubernetes.
• Familiarity with cloud platforms such as AWS, Azure, or GCP.
• Knowledge of additional No
  
  SQL databases beyond MongoDB.
• Open‑source contributions that demonstrate technical depth and community engagement.
• Background working in agile, fast‑paced engineering environments with iterative delivery cycles.

• Bachelor's degree/University degree or equivalent experience
• Master's degree preferred

At Citi, you will work on backend systems that operate at global scale, supporting financial services used by millions of clients worldwide. We invest in our engineers - providing the tools, challenges, and environment to do meaningful, high‑impact work.

• Hybrid working model, with 3 days in the office and 2 days working remotely, giving you flexibility while staying connected to your team.
• Exposure to complex, large‑scale engineering challenges across a modern stack including Apache Kafka, MongoDB, Elasticsearch, and reactive Java frameworks.
• Opportunities to grow technically and lead — mentoring engineers, defining standards, and influencing architectural decisions at a global institution.
• Access to structured learning and development programmes to deepen your technical expertise and accelerate your career progression.
• Competitive compensation package with financial wellbeing support and access to employee assistance programmes.
• A collaborative engineering culture with global reach, working alongside specialists across technology, product, and architecture.

This job description provides a high‑level review of the types of work performed. Other job‑related duties may be assigned as required.

• Strong understanding of data structures, algorithms, and object‑oriented design principles.
• Ex…