Senior Data Migration Engineer (Java)

The Role As a Senior Data Migration Engineer, you will be a core execution member of the dedicated migration squad. You will work hands-on across the full migration lifecycle - from extraction and mapping through conversion, validation, and cutover - while also actively building the tooling and accelerators that make future migrations faster and safer (e.g.: artifact observability, version-controlled mapping pipelines, automated validation checks, and reusable migration templates). This is not a maintenance role: you will shape the process, own the tooling, and directly influence delivery velocity.  IN SHORT: 🌍 Remote work or on-site (Wrocław, Bielsko-Biała) – your choice! 💰135 - 170 PLN/h + VAT ☑️ B2B contract What You'll Get: • End-to-end ownership of complex, high-stakes technical deliveries. • Direct contribution to tooling that will outlive the programme and be reused across 50+ customer migrations.  • A growing role: as the programme industrializes, senior engineers are expected to mentor and technically lead parallel migration teams.  • Exposure to a full modern stack (Java 21 / React / PostgreSQL / AWS) alongside legacy Smalltalk systems.   • Long-term engagement with clear phase gates and the possibility to grow into a Lead Engineer role.  Data Migration & Legacy Systems experience • Proven experience with large-scale data migration projects: ETL or systems integration on enterprise-scale projects, transformation pipelines, cutover planning.  • Experience working with XML-based data transformation (mapping files, XSLT, or equivalent config-driven ETL).  • Proven ability to diagnose complex migration errors under time pressure: root-cause analysis, staging data fixes, re-run coordination. • Experience coordinating with business stakeholders during UAT and cutover; clear written and verbal communication in English.  • Experience with legacy database analysis: reverse-engineering un(der)documented schemas, understanding data semantics and relationships without complete documentation and dealing with corrupted or ambiguous data or metadata.  Technical Skills • Comfortable working with SQL at an advanced level: complex queries, schema analysis, data profiling, and diagnosing data quality issues.  • Strong proficiency in SQL across at least two of: PostgreSQL, Oracle, SQL Server, DB2.  • Solid Java skills (Java 21 ecosystem preferred); comfortable building and extending internal tooling - data pipelines, automation scripts, validation frameworks - with clean, testable code.  • Familiarity with Git workflows, CI/CD pipelines, and infrastructure-as-code practices.   • Good exposure to cloud environments, ideally AWS infrastructure and services.  • Docker: confident setup, troubleshooting, and local environment management.  Domain & Governance • Rapid domain understanding: ability to quickly absorb unfamiliar, regulated business domains.   • Governance mindset: documenting decisions, maintaining audit trails, getting formal client sign-off.   • Experience working with subject matter experts to define and validate data transformations and mappings.  Mindset & Working Style • Ability to manage multiple concurrent workstreams.  • Clear communicator: able to explain architectural and domain modelling decisions to both technical and non-technical stakeholders.  • Resilient and persistent under pressure: comfortable working with tight deadlines and high client expectations.  • Actively uses AI-assisted tools (e.g. ChatGPT, Claude, GitHub Copilot or similar) as part of daily development and problem-solving workflow - we expect AI tools to be a natural part of how you work.  Nice to haves: • Exposure to Smalltalk or ObjectStudio.   • Familiarity with S3-compatible object storage, artifact lifecycle management, or observability tooling (dashboards, trend analysis).  • Experience with cloud-native deployments on AWS; understanding of multi-tenant SaaS architectures.  • Debt management, financial services, or accounts receivable domain experience is a significant advantage. • German language skills (B2+).  Reasons Why You Would Enjoy Working With Us • We work in the latest technologies and with international clients, and our projects are polished from < to /> - learn about some of the projects we have completed. • We organize TechTalks, meet-ups and create guilds where we exchange knowledge - you can learn a lot from your teammates. • We have a close-knit team and we make sure to have regular integrations - we often go out to celebrate together. • You can work remotely or choose to work from our offices in Wroclaw or Bielsko-Biala. However, we count on your openness to occasionally visit the office for team meetings or client visits, or possible occasional trips to the client's headquarters. • You can adjust your working hours to suit your needs, starting your day between 7:00 and 10:00 am. • You can work with great specialists in their fields who also have a sense of humor and other after-hours hobbies. It is the people who create the unique atmosphere and relaxed atmosphere at CSHARK. • We have a flat structure - we are not a corporation and don't want to be one 🙃. • We offer bonuses for employee referrals (from 3000 PLN to 7000 PLN). • We organize remote English classes and provide access to the company library. You can also become an author/author of articles published on our technical blog - https://cshark.com/blog/.