Senior Software Engineer - Core Java & Apache Spark

Citi; New York (NY); On-site; USD 120,000 - 160,000; Full time

Job summary

Citi is hiring a Senior Software Engineer in New York to build and scale core data processing systems. The role demands deep expertise in Java and Apache Spark, focusing on both architecture and implementation of critical systems.

The ideal candidate has expert-level skills in JVM tuning, distributed systems design, and performance optimization. You will also mentor junior engineers and lead code reviews while adhering to best practices like SOLID and TDD.

Qualifications

• Expert-level proficiency in Java, including Collections Framework and Java Concurrency API.
• Proven experience with Apache Spark for large-scale data transformations.
• Extensive experience with Spring Boot and Spring Data in production environments.

Responsibilities

• Architect and build high-throughput data pipelines using Apache Spark.
• Optimize JVM performance and tune garbage collection.
• Implement scalable distributed systems and lead technical reviews.

Skills

Core Java

Apache Spark

Spring Framework

Data Structures & Algorithms

Containerization

Database Engineering

Tools

Docker

Kubernetes

SQL

NoSQL databases

Job description

Senior Software Engineer - Core Java & Apache Spark

We are hiring an elite Senior Software Engineer to build and scale our core data processing and application infrastructure. This role demands deep, hands‑on expertise in the Java ecosystem and distributed computing with Apache Spark. You will be responsible for the architecture, design, and implementation of mission‑critical systems that process massive datasets, requiring a mastery of concurrency, JVM internals, and modern cloud‑native patterns.

Key Responsibilities:

• Architect & build high‑throughput, low‑latency data processing pipelines using Apache Spark and the Spring ecosystem.
• Performance engineering: dive deep into JVM internals, garbage collection tuning, and Spark job optimization to maximize performance and resource efficiency.
• Distributed systems design: implement scalable, resilient, and transactional architectures leveraging container orchestration (Kubernetes/OpenShift) and distributed data stores.
• Code & design excellence: champion and enforce best practices in software engineering, including SOLID principles, advanced design patterns, Domain‑Driven Design (DDD), and Test‑Driven Development (TDD).
• Database mastery: engineer and optimize data models for both relational and NoSQL databases, ensuring data integrity, performance, and scalability.
• CI/CD automation: own and enhance CI/CD pipelines for automated build, test, and deployment of Java applications and Spark jobs in a containerized environment.
• Technical leadership: lead design and code reviews, mentor junior engineers, and drive the adoption of new technologies and architectural patterns across the team.

Required Technical Qualifications:

• Core Java & JVM: expert‑level proficiency in Java, including the Collections Framework, Lambdas, and the Java Concurrency API. Demonstrable experience tuning the JVM and troubleshooting memory/GC issues.
• Apache Spark: proven, hands‑on experience developing, deploying, and tuning complex Spark applications for large‑scale data transformation and analysis.
• Spring Ecosystem: extensive, practical experience with the Spring Framework, particularly Spring Boot, Spring Data, and Spring Batch in a production environment.
• Data Structures & Algorithms: deep understanding of fundamental data structures and algorithms, with a focus on their application in distributed computing and performance‑critical systems.
• Containerization & Cloud‑Native: hands‑on experience with Docker for building images and Kubernetes/OpenShift for deploying and managing distributed applications.
• Database Engineering: strong command of SQL and relational database design, including transaction management and indexing. Experience with at least one production NoSQL database (MongoDB, Graph DB, etc.).
• Architectural Design: practical application of OOP, SOLID, and DDD principles to build maintainable and scalable systems. You write tests first (TDD) and believe in robust, automated testing.

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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