Data Engineer

Unchain Data; Kraków; Hybrid; PLN 140,000 - 210,000; Full time

Job summary

Unchain Data in Kraków is seeking a data engineer to own the data lakehouse architecture and ensure accurate, governed data across lake layers. You will manage ingestion via CDC, design layouts for speed and cost, and uphold retention and regulatory requirements.

The role focuses on open formats (Iceberg/Delta/Hudi), partitioning, and SQL/data modeling to support analytics, finance, and regulators with minimal drift from source systems.

Qualifications

• 3+ years in data engineering with real ownership of a large-scale data lake/lakehouse.
• Cloud object storage (S3/GCS) plus Snowflake, Databricks, or BigQuery in production.
• Hands-on with Iceberg, Delta, or Hudi open table formats.
• Deep understanding of partitioning, file layout, and query optimization at terabyte-plus scale.
• CDC and streaming ingestion experience (Kafka + Debezium or equivalent).
• Strong SQL and data modeling; ability to reason about OLTP systems and ledgers.
• Data lake governance: catalogs, lineage, access control, PII, retention.
• Python and an orchestrator (Airflow/Dagster) as tools for architecture and ownership.

Responsibilities

• Own the lakehouse architecture: bronze/silver/gold layers, Iceberg/Delta tables, schema evolution.
• Land operational data via CDC streaming (Kafka, Debezium), handling late and duplicate events.
• Design data layout for speed and cost: partitioning, compaction, file sizing, query performance on Trino/Athena/Snowflake.
• Own retention and archival: storage tiering, regulatory retention, immutability, GDPR deletion.
• Guarantee correctness: freshness SLAs, drift detection, reconciliation against source wallets and ledgers.
• Own governance: catalog and lineage, row/column access control, PII masking, encryption, audit trails.
• Monitor ingestion health, data anomalies, and cloud storage/compute spend.

Skills

Data lake ownership

SQL proficiency

Python

Data modeling

Regulatory awareness

Cloud platform understanding

Tools

Iceberg

Delta Lake

Kafka

Debezium

Airflow

Dagster

Snowflake

Databricks

BigQuery

Trino

Job description

The Role

You'll own the data lake — the system of record for millions of financial events a day across millions of active users. You decide how that data lands, is stored, retained, and governed on S3 + Snowflake/Databricks, so analytics, finance, and regulators all see accurate, reconciled data with zero drift from source.

Responsibilities

• Own the lakehouse architecture: bronze/silver/gold layers, Iceberg/Delta tables, schema evolution.
• Land operational data via CDC streaming (Kafka, Debezium), handling late and duplicate events.
• Design data layout for speed and cost: partitioning, compaction, file sizing, query performance on Trino/Athena/Snowflake.
• Own retention and archival: storage tiering, regulatory retention, immutability, GDPR deletion.
• Guarantee correctness: freshness SLAs, drift detection, reconciliation against the source wallet and ledger systems.
• Own governance: catalog and lineage, row/column access control, PII masking, encryption, audit trails.
• Monitor ingestion health, data anomalies, and cloud storage/compute spend.

Requirements

• 3+ years in data engineering, with real ownership of a large-scale data lake or lakehouse.
• Cloud object storage (S3/GCS) plus Snowflake, Databricks, or BigQuery in production.
• Hands-on with an open table format (Iceberg, Delta, or Hudi).
• Deep understanding of partitioning, file layout, and query optimization at terabyte-plus scale.
• CDC and streaming ingestion experience (Kafka + Debezium or equivalent).
• Strong SQL and data modeling; enough relational grounding to reason about the OLTP systems you capture from — critical for financial ledgers.
• Data lake governance: catalogs, lineage, access control, PII, retention.
• Python and an orchestrator (Airflow/Dagster) as tools — this is an architecture and ownership role, not heads-down coding.

Nice to Have

• Experience in fintech, iGaming, or another regulated, audit-heavy environment.