Senior Java Backend Engineer

Citi; Mississauga; Hybrid; CAD 121,000 - 171,000; Full time

Benefits offered by this job

Hybrid work model (3 days in office, 2

Global scale backend systems

Job summary

Citi in Canada is hiring a senior backend engineer to build scalable Java services using Spring WebFlux and reactive programming. You will develop asynchronous microservices, stream events with Kafka, and ensure high availability at global scale.

You will mentor peers, champion TDD with JUnit, and collaborate with product, infra, and architecture teams to drive architectural decisions. The role offers a hybrid schedule and exposure to a modern stack including Elasticsearch and MongoDB.

Qualifications

• 6-10 years backend development with Java focus.
• Strong Java 8+ with functional programming and reactive stack.
• Experience with Spring WebFlux, Project Reactor, or RxJava.
• Kafka for event streaming and real-time pipelines.
• MongoDB data modelling and Elasticsearch analytics.
• JUnit-based TDD and high test coverage.
• Git-based collaboration, PR reviews, GitFlow, and CI/CD.

Responsibilities

• Build and deploy asynchronous, event-driven Java microservices.
• Design reactive services to meet throughput and latency targets.
• Develop real-time pipelines using Apache Kafka.
• Engineer search/analytics with Elasticsearch and data persistence with MongoDB.
• Lead tests and code reviews to improve quality.
• Mentor mid-level engineers and align with product/infra teams.

Skills

Java (8+)

Spring WebFlux

Reactive programming

Project Reactor

RxJava

Apache Kafka

MongoDB

Elasticsearch

JUnit

Git workflows

CI/CD

Education

Bachelor's degree

Master's degree (preferred)

Tools

Docker

Kubernetes

AWS/Azure/GCP

RESTful API design

Job description

Responsibilities

• Build and deploy asynchronous, event-driven microservices in Java, ensuring high availability and performance at scale.
• Design reactive backend services using Spring WebFlux, 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.

Required qualifications & skills

• 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 WebFlux, Project Reactor, or RxJava.
• Hands‑on experience building and integrating event streaming systems with Apache Kafka.
• Solid command of MongoDB for NoSQL 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 GitFlow.
• Familiarity with CI/CD pipeline design to support automated testing and continuous deployment processes.

Beneficial skills & qualifications

• Experience containerising and orchestrating applications using Docker and Kubernetes.
• Familiarity with cloud platforms such as AWS, Azure, or GCP.
• Knowledge of additional NoSQL 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.

Education

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

What we offer

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.
• Experience with RESTful API design and development.
• Familiarity with cloud platforms (e.g., AWS, Azure, GCP) is a plus.
• Excellent problem‑solving, analytical, and debugging skills.
• Ability to work independently and as part of a collaborative team.

Please see the requirements listed above.

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.

If you are a person with a disability and need a reasonable accommodation to use our search tools and/or apply for a career opportunity review Accessibility at Citi.

View Citi's EEO Policy Statement and the Know Your Rights poster.

Primary Location Full Time Salary Range: $120,800.00 - $170,800.00

This job opening is for an existing job vacancy.