Senior Java Developer – Risk Technology

SQUARE ONE RESOURCES sp. z o.o.; Warszawa; Hybrid; PLN 180,000 - 300,000; Full time

Job summary

SQUARE ONE RESOURCES sp. z o.o. in Warszawa seeks a Senior Java Developer to join a global Risk Technology team responsible for designing, developing, and maintaining high‑performance data processing systems.

You will help deliver strategic technology initiatives and scalable enterprise capabilities. The role demands strong backend Java expertise, multi‑threading and REST API design, and performance tuning, plus collaboration with engineers, architects, and business stakeholders across regions

Qualifications

• Strong Java development experience and backend design skills.
• Advanced knowledge of Java concepts and best practices.
• Hands-on with multi-threading and concurrent programming.
• Proven experience designing and developing Java REST APIs.
• Experience with large-scale, high-volume data processing systems.
• Strong understanding of relational databases (RDBMS) and SQL.
• Experience with JVM performance analysis and optimization.
• Ability to troubleshoot and optimize backend application performance.

Responsibilities

• Translate business requirements into effective technical solutions.
• Collaborate with stakeholders and technical teams to deliver high-quality software.
• Troubleshoot complex technical issues and optimize application performance.
• Analyze and improve JVM performance and application scalability.
• Ensure high code quality by applying software engineering best practices.
• Participate in code reviews, CI/CD processes, and continuous improvement initiatives.
• Work closely with distributed technology teams located across different regions.
• Contribute to maintaining stable and reliable production environments.
• Design, develop, and maintain enterprise applications based on Java technologies.

Skills

Java development

Java concepts & best practices

Multi-threading & concurrency

Java REST APIs

Large-scale data processing

RDBMS & SQL

JVM performance analysis

Backend performance optimization

Tools

PostgreSQL

Oracle PL/SQL

Docker

Kubernetes

Linux shell scripting

Python scripting

Apache Kafka

Job description

Nasze wymagania:

• Strong professional experience with Java development.
• Advanced knowledge of Java programming concepts and best practices.
• Hands-on experience with multi-threading and concurrent programming.
• Proven experience designing and developing Java REST APIs.
• Experience building and maintaining large-scale, high-volume data processing systems.
• Strong understanding of relational databases (RDBMS) and SQL.
• Experience with JVM performance analysis and optimization.
• Ability to troubleshoot and optimize backend application performance.

Mile widziane:

• Experience with PostgreSQL.
• Knowledge of Apache Kafka and event-driven architectures.
• Experience with Oracle PL/SQL and SQL query optimization.
• Knowledge of Linux Shell scripting.
• Experience with Python scripting.
• Exposure to functional programming concepts (e.g., Haskell).
• Experience with Docker and Kubernetes (K8S).
• Understanding of DevOps practices and CI/CD pipelines.

O projekcie:

We are looking for a Senior Java Developer to join a global Risk Technology team responsible for designing, developing, and maintaining high-performance data processing systems supporting risk management functions. The role focuses on delivering strategic technology initiatives, developing new application capabilities, enhancing existing solutions, and ensuring the stability, scalability, and performance of enterprise-level platforms. The successful candidate will collaborate with a global team of software engineers, architects, project managers, technical specialists, and business stakeholders to deliver robust and scalable technology solutions. This position requires strong backend development expertise, experience with distributed systems, and the ability to work independently across the full software development lifecycle.

Zakres obowiązków:

• Translate business requirements into effective technical solutions.
• Collaborate with business stakeholders and technical teams to deliver high-quality software.
• Troubleshoot complex technical issues and optimize application performance.
• Analyze and improve JVM performance and application scalability.
• Ensure high code quality by applying software engineering best practices.
• Participate in code reviews, CI/CD processes, and continuous improvement initiatives.
• Work closely with distributed technology teams located across different regions.
• Contribute to maintaining stable and reliable production environments.
• Design, develop, and maintain enterprise applications based on Java technologies.
• Develop new functionalities and improve existing application components.