Senior Java Software Engineer – AI-Driven Modernisation (f/m/x)

We’re building a next-generation technology team focused on modernising critical financial services through AI-first engineering. You’ll play a key role in transforming complex legacy systems into modern, scalable, and intelligent solutions. You’ll work hands-on with the latest AI tools to accelerate development, improve code quality, and deliver measurable impact across the organization.

Sii ensures that all employment-related decisions are made solely on the basis of qualifications and competencies. We are committed to equal treatment of all individuals, regardless of any protected characteristics, and promoting a diverse and inclusive work environment.

Your tasks

• Modernizing legacy systems using AI to analyze, refactor, and optimize existing codebases

• Implementing modern architecture patterns, including strangler fig and microservices migration approaches

• Delivering production-ready services with robust testing, clear documentation, and multi-instance deployment support

• Using AI tools throughout the SDLC to boost productivity and ensure faster delivery cycles

• Collaborating with cross-functional teams to ensure smooth service transition and ownership handover

• Demonstrating measurable improvements in performance, reliability, and API efficiency

Requirements

• Minimum 7 years of professional experience in Java programming

• Experience with legacy system refactoring or service modernization projects

• Hands-on experience with AI-powered development tools (e.g., GitHub Copilot, Claude Code, or similar LLMs)

• Solid understanding of CI/CD, automated testing, and cloud-native architectures

• Ability to design scalable, secure, and maintainable software solutions

• Willingness to travel to Krakow for short business delegations as needed

• Excellent command of English, both written and spoken, enabling effective communication in an international environment

• Residing in Poland required