Senior Data Engineer

• Position: Senior Database Engineer

• Location: Kraków, Poland

• Working mode: Initially remote; once the Kraków office is ready, 3-4 days per week onsite

About our client

Our client is an Israeli sports-tech company combining advanced data engineering, AI/ML and mathematical modelling to build high-performance real-time sports analytics solutions. The company processes large volumes of real-time data across sports including football, basketball, baseball and American football, transforming it into predictions and actionable insights. Its technology supports data-driven organizations operating in environments where speed, scalability and data accuracy are critical. The company is now building its new R&D team in Kraków, giving engineers the opportunity to join at an early stage and help shape the technical foundations of the new organization.

The Role

You'll own our data lake and lakehouse architecture - the system of record for millions of financial events every day, generated by 12M+ active users, including bets, wallet movements and live odds.

You will be responsible for how data lands, is stored, retained, governed and made available across AWS S3, Snowflake and Databricks. Your work will ensure that analytics, finance and regulatory teams have accurate, reconciled data with no drift from source systems.

This is an architecture and ownership role rather than a heads-down coding position. You'll make key decisions around data architecture, performance, reliability, governance and cost.

What you'll be doing

• Own the lakehouse architecture, including bronze/silver/gold layers, Iceberg/Delta tables and schema evolution.

• Design and maintain CDC-based streaming ingestion using Kafka, Debezium or equivalent, including handling late and duplicate events.

• Design data layouts for performance and cost efficiency, including partitioning, compaction, file sizing and query optimization across Trino, Athena and Snowflake.

• Own data retention and archival, including storage tiering, regulatory retention, immutability and GDPR deletion.

• Guarantee data correctness through freshness SLAs, drift detection and reconciliation against source wallet and ledger systems.

• Own data governance, including catalog and lineage, row/column-level access control, PII masking, encryption and audit trails.

• Monitor ingestion health, data anomalies and cloud storage/compute spend.

• Work closely with engineering, analytics, finance and other stakeholders to ensure the data platform supports business and regulatory requirements.

What we're looking for

• 3+ years of experience in data engineering, with real ownership of a large-scale data lake or lakehouse.

• Production experience with cloud object storage such as AWS S3 and Snowflake, Databricks or BigQuery.

• Hands-on experience with an open table format: Iceberg, Delta or Hudi.

• Deep understanding of partitioning, file layout and query optimization at terabyte-plus scale.

• Experience with CDC and streaming ingestion, preferably Kafka + Debezium or equivalent.

• Strong SQL and data modelling skills, with a good understanding of relational/OLTP systems and financial data flows.

• Experience with data lake governance: catalogs, lineage, access control, PII, retention and security.

• Python and an orchestrator such as Airflow or Dagster - used as tools rather than being the primary focus of the role.

• Nice to have: experience in fintech, iGaming or another regulated, audit-heavy environment.

Why this role is interesting

• You'll have real ownership of a critical data platform, rather than simply implementing tasks defined by someone else.

• You'll work with large-scale financial data, where correctness, traceability and reliability are critical. The role gives you the opportunity to influence architecture, technology choices, data governance, performance and cloud costs.

• The scale is significant: 12M+ active users and millions of financial events processed every day.

What We Offer

• Opportunity to join a new R&D organization in Kraków and help shape its technical foundations from the beginning.

• B2B or perm contract (UoP)

• Initially fully remote work, followed by a hybrid model with 3-4 days per week from the Kraków office once the office is ready.

• Opportunity to work with high-volume transactional and real-time data systems serving millions of active users.

• International environment and collaboration with experienced technical teams and company leadership.

• Competitive compensation and the equipment required to perform the role.

• Opportunity to work on challenging problems around database scalability, data consistency, performance and real-time processing.