Lead Data Migration Engineer (.NET)

The Role

You will lead the data migration workstream for a compliance-critical public-sector registry system.

The core challenge: converting a fully normalised relational database into an event-sourced architecture, migrating large volumes of document files, and ensuring every data related decision is documented and approved by the client.

This is not a standard backend role. You need to understand legacy data deeply, make domain-informed decisions under uncertainty, and deliver under tight timelines with high client visibility.

IN SHORT:

🌍 Remote work or on-site (Wrocław, Bielsko-Biała) – your choice!

💰145 - 170 PLN/h + VAT

☑️ B2B contract

Data Migration & Legacy Systems experience

• Proven experience with large-scale data migration projects: ETL, transformation pipelines, cutover planning.

• Hands-on experience with event sourcing (relational-to-event model transformation): decomposing relational data into domain events with deterministic ordering.

• Experience with legacy database analysis: reverse-engineering un(der)documented schemas, understanding data semantics and relationships without complete documentation.

• Experience with data quality handling: nulls, duplicates, inconsistent formats, missing fields, validation rules.

• Familiarity with document/file migration at scale: metadata extraction, filename parsing, large-volume validation and dealing with corrupted or ambiguous data or metadata.

Core Skills

• Strong knowledge of backend design patterns (dependency injection, repository, mediator, factory).

• English language skills (B2+ minimum): required for clear communication with stakeholders and documentation of architectural decisions.

• Hands-on experience with CQRS, Domain-Driven Design, and Event Sourcing.

• Ability to design and implement aggregates, entities, value objects, and bounded contexts.

• Skilled in building systems that enforce clear separation of concerns, scalability, and maintainability.

• Solid understanding of clean architecture principles.

Technical Skills

• Strong experience with .NET / C# backend development.

• Practical knowledge of Modular Monolith.

• Experience with PostgreSQL and modern ORM frameworks (e.g. Entity Framework or equivalent).

• Experience with Marten DB or willingness to learn quickly.

• Exposure to CosmosDB or similar NoSQL/document databases.

• Experience designing and consuming RESTful APIs.

• Docker: confident setup, troubleshooting, and local environment management.

• Good exposure to cloud environments, ideally Azure infrastructure and services.

• Comfortable working with SQL at an advanced level: complex queries, schema analysis, data profiling, and ad-hoc investigation of production data.

Domain & Governance

• Rapid domain understanding: ability to quickly absorb unfamiliar, regulated business domains (registries, compliance, legal records).

• 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.

• Public-sector, institutional or regulatory software experience is a significant advantage.

Mindset & Working Style

• Proactive problem solver: you find workarounds when blocked, explore alternatives, and escalate intelligently - you don’t stop and wait.

• Autonomous: you structure your own work, identify next steps, and act without being prompted. You take ownership of your deliverables.

• Curious about data: you enjoy investigating legacy systems.

• Comfortable with ambiguity: you make progress when not everything is defined, and revisit decisions as understanding grows.

• Pragmatic engineer who can balance domain purity with real-world business needs.

• Strong stakeholder engagement: you proactively reach out to SMEs, business analysts, and client representatives, challenge assumptions, and drive clarity.

• Clear communicator: you are able to explain architectural and domain modelling decisions to both technical and non-technical stakeholders.

• Resilient and persistent under pressure: you are comfortable working with tight deadlines, high client expectations and compliance scrutiny.

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/.