Olena R — Senior Data Engineer with SAP BW and Databricks

Data Engineer / Analytics Engineer - Fintech Platform

Duration: 2025 – August 2026

Summary:

• Own production pipelines end to end on a Delta Lake medallion lakehouse (Databricks / Microsoft Fabric): ingestion from provider REST APIs, internal services and file feeds; PySpark and Spark SQL transformation; curated marts, scheduling and monitoring.
• Migrated and unified chargeback data from six acquirers and PSPs (Stripe, Checkout.com, Revolut, Worldpay and others) into one canonical 31-column schema — each with a different payload shape and dispute lifecycle — then built the dimensional model and reporting layer on top.
• Design the Gold-layer marts the business queries — star and galaxy schemas with conformed customer, product and transaction dimensions and standardised metric definitions — so the same question returns the same number regardless of who asks.
• Validate migrated datasets against source with business and technical stakeholders: reconciliation batteries, control totals, coverage and freshness guards and record-level diffs — run inside the pipeline, not as a one-off sign-off.
• Build ETL/ELT for regulatory and management reporting: AML alerting across fiat (IBAN) and crypto (wallet) domains, risk scoring, transaction monitoring and a regulator-facing migration report.
• Optimise Spark performance and cost — rebuilt a full-year table scan as a rolling 30-day window, cutting runtime sharply and keeping the pipeline scalable as volume grew.
• Trace data defects to source rather than patching downstream: a legal-entity misclassification traced to a case-sensitive regex, a settlement gap caused by an INNER JOIN silently dropping records — each fixed at source and restated.

Technologies: Databricks, Delta Lake, Microsoft Fabric, PySpark, Spark SQL, REST APIs, Azure, Data Factory

Data Engineer — People & Business Analytics - Confidential (NDA) (Multi-brand Consumer & iGaming Group Reporting)

Duration: 2025 – 2026

Summary: Development of weekly and monthly reporting pipelines for a multi-brand consumer and iGaming group, integrating HRIS and operational revenue data to produce consolidated business metrics across multiple brands and projects.

Achievements:

• Built the group's weekly and monthly reporting pipelines in Python against PostgreSQL on Azure — scheduled extraction from an HRIS mirror, transformation, validation and automated delivery.
• Connected operational revenue data in Amazon Athena with headcount denominators to produce per-brand business metrics, including a brand-to-project mapping layer (21 brands into 9 projects) that made cross-source aggregation possible at all

Technologies: Python, PostgreSQL, Azure, Amazon Athena

Product Owner — Data & Platform Delivery (Financial Services, Retirement & Wealth Platform)

Duration: 2025 – Present

Summary: Product ownership and delivery coordination for a US-based financial services platform focused on retirement and wealth management, working closely with engineering teams to ensure data correctness and system integration in a regulated environment.

Responsibilities:

• Collaborated daily with US engineering teams across two delivery teams.
• Managed requirements, data correctness, system cutover, and integration logic.
• Communicated effectively in English within a large regulated enterprise.

Business / Data Analyst - InGain (Digital Lending Platform)

Duration: 01/2025 – 10/2025

Summary: Modeling and integration of lending platform data into the data warehouse, including applications, transactions, and user flows, with development of a reporting layer to support business insights.

Responsibilities:

• Modeled lending platform data and integrated it into the warehouse.
• Built reporting layers on top of integrated data.

Application Analyst — Data & Reporting - BMW – CoStCo (Enterprise Platform)

Duration: 11/2022 – 01/2025

Summary: Analysis and reporting on large Oracle datasets within a global enterprise environment, including data model design and end-user training to support management reporting and decision-making.

Responsibilities:

• Delivered analysis and reporting on large Oracle datasets with SQL, Python and SPSS inside a global enterprise landscape; designed the data models and trained end users on them.
• Found and fixed a production data-integrity issue that had distorted quarterly management reporting for years — a legacy filter excluding whole transaction types; corrected the historical models and presented impact and mitigation to senior stakeholders.

Technologies: Oracle, SQL, Python, SPSS

Earlier Experience

System Analyst / Technical Writer - IORYS (Compliance & Regulatory Documentation)

Duration: 10/2023 – 04/2024

Summary: Mapping data flows and producing ISO-compliant documentation of processes and system requirements to support compliance and regulatory needs.

Responsibilities:

• Mapped data flows and documented system requirements.
• Produced ISO-compliant process documentation.

Senior System Analyst - Via SMS (Financial Services Platform)

Duration: 06/2022 – 10/2022

Summary: Platform and data-flow analysis for a financial services company, supporting business and technical requirements.

Responsibilities:

• Analyzed platform and data flows.

Business Analyst - Intrum (Debt Management Platform)

Duration: 01/2022 – 06/2022

Summary: Data quality remediation and CRM integration analysis for a debt management platform in Switzerland.

Responsibilities:

• Performed platform and data-flow analysis for financial-licence application.
• Remediated CRM integration data quality issues.

Senior Business & Data Analyst (Freelance Engagements)

Duration: 09/2011 – 2022

Summary: Multiple long-term engagements across fintech, insurance, iGaming, and enterprise domains involving source-to-target mapping, SQL modeling, and ETL specification development.

Responsibilities:

• Performed source-to-target data mapping.
• Developed SQL models and ETL specifications.

Technologies: SQL