Senior Data Migration Engineer (Java)

The RoleAs 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 contractWhat 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 SkillsComfortable 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 & GovernanceRapid 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 StyleAbility 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 UsWe 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/.