Senior Java Performance Engineer

Java 21 | Spring Boot | Azure SQL Hyperscale | Apache Storm | Cloud Modernization

📍 Kraków | Hybrid – 3 days per week in the office
💰 Rate: up to 1,350 PLN/day

Performance is your passion. Optimization is your superpower.

Are you a Senior Java Engineer who loves digging deep into complex systems, solving challenging performance issues, and making mission-critical applications run at their best?

We're looking for an experienced Senior Java Performance Engineer to join a global engineering team in the banking and financial services industry. You'll work on platforms supporting portfolio performance reporting, helping financial advisors, operations teams, and clients access accurate information about portfolio returns, asset allocation, and holdings.

This role goes beyond writing code. You'll combine advanced Java development with database optimization, distributed processing, production troubleshooting, and cloud modernization. If execution plans, CPU bottlenecks, and large-scale batch processing sound like challenges you'd enjoy solving, we'd love to hear from you!

🚀 What will you do?

• Build and modernize Java applications: Develop and maintain Java 21 and Spring Boot batch applications and microservices, including major framework and dependency upgrades.

• Optimize distributed processing: Operate, troubleshoot, and tune an Apache Storm-based processing cluster, covering worker balancing, restarts, and alert configuration.

• Master database performance: Analyze and optimize SQL Server and Azure SQL Hyperscale workloads through execution plans, indexing, query tuning, and troubleshooting performance regressions.

• Drive cloud modernization: Help migrate mainframe batch jobs and DB2 data flows to Azure as part of a broader platform modernization initiative.

• Keep critical processes running: Monitor nightly batch performance against service-level targets, investigate production incidents, lead root cause analysis, and implement lasting fixes.

• Strengthen application security: Address open-source dependency vulnerabilities using Nexus IQ or similar Software Composition Analysis (SCA) tools, ensuring appropriate risk assessment and sign-off.

• Collaborate across teams: Work closely with data, cloud, QA, application support, and external technology partners to deliver reliable, high-performing solutions.

🧠 What we're looking for

• A degree in Computer Science or a related field is preferred.

• 18+ years of hands-on Java development experience, ideally within banking or financial services.

• Strong Java 17/21 and Spring Boot expertise, including experience with major framework upgrades — must-have.

• Proven SQL Server / Azure SQL performance tuning experience, ideally with Azure SQL Hyperscale, including execution plan analysis, query optimization, plan regression troubleshooting, and CPU bottleneck resolution — must-have.

• Hands-on experience with distributed or stream processing technologies, such as Apache Storm, Kafka Streams, or Apache Flink — must-have.

• Experience with DB2 and understanding or migrating mainframe batch jobs — an advantage.

• Familiarity with Azure Kubernetes Service (AKS), Helm, and Azure AD / Microsoft Entra ID integration — an advantage.

• Experience resolving open-source vulnerabilities using Nexus IQ or similar SCA tools — an advantage.

• Background in wealth management or portfolio performance, including returns calculations, holdings, and valuation data — an advantage.

• A strong understanding of Agile, Test-Driven Development (TDD), and DevOps practices.

• Excellent analytical and problem-solving skills, attention to detail, and a proactive approach to troubleshooting.

• Strong communication skills, with the ability to engage effectively with engineering teams, senior stakeholders, and external vendors.

• A collaborative mindset and experience working with globally distributed teams in a diverse environment.

👥 Meet your team

You'll join the Portfolio Performance Reporting team within Digital Intelligence & Advisor Platforms.

The team builds and operates platforms responsible for calculating and reporting portfolio returns, asset allocation, and holdings for financial advisors, operations teams, and clients.

You'll work in a collaborative, globally distributed environment alongside specialists in data, cloud, QA, and application support. Quality, reliability, and continuous improvement are at the heart of everything the team delivers.

✨ Why join this project?

• Work on business-critical platforms within the banking and financial services industry.

• Tackle complex performance challenges across Java, distributed processing, and Azure SQL.

• Contribute to a major modernization program involving cloud technologies and legacy systems.

• Collaborate with experienced international engineering teams and external technology partners.

• Make a tangible impact on the performance, stability, and security of enterprise applications.

Ready to take on complex performance challenges and help modernize critical financial platforms?

Apply now and let's talk!