Kostiantyn Flisiuk

Databricks Data Engineer | Automated Data Testing, Reconciliation & Traceability | 10 yrs in Data, 8 in Banking

Warsaw, Poland🇺🇦 Ukrainian

Joined Oct 2026

Male

I build automated data testing for diverse Databricks projects: reconciliation, traceability and data quality checks that run beside the build team and flag where data breaks requirements. 10 years in financial and risk data. Remote B2B contracts, 3–6 months.

2025-2026, Databricks/PySpark:
• Global consumer goods: ETL and business-logic QA framework
• Global snacks maker (recovery): specs and multi-region QA framework
• European beverage bottler: SQL-to-Databricks redevelopment, 100+ test suite; extended client's Traceability QA framework

How I work:
• Read what exists, define "correct", prove it with executable tests
• Business logic in SQL, automation in PySpark: readable by analysts
• Configurable per environment and region; documented handover

Since 2015, before AI assistants: hand-built SQL/Python solutions from docs, debugger and terminal.
• PKO Bank Polski: business intelligence solutions; reporting automation; overtime and absence fraud investigation; experimental ML attrition model
• NatWest Markets: Balance Sheet control from source systems to consolidation, variance root-causing, Fair Value Levelling
• Tier-1 EU bank: IFRS 9 / New DoD redevelopments of PD/LGD/EAD model data
Department AI SPOC (2024–2026): AI-assisted delivery on tight deadlines with simple, verified code; no AI dependency; Local AI case study for specific projects.

Focus: data testing, risk/regulatory data quality (IFRS 9, BCBS 239), anti-fraud/cybersecurity data, AI adoption for data teams.

Experience

Lingaro
Lead Consultant - Data Engineer (Databricks)
Dec 2025 - Aug 2026 · 8 months · Hybrid
Global consumer goods: QA framework for ETL pipelines and business-logic compliance (Soda, PySpark). Global snacks maker (recovery): rebuilt data specifications and a multi-region QA framework (pydeequ, PySpark) in 1 month vs 3-4 planned. European beverage bottler: SQL-to-Databricks redevelopment with a 100+ test suite, per-region configs and runtime benchmarks on synthetic data; extended the client's Traceability QA Framework.
DatabricksApache SparkSQL
Lead Consultant - Data & Business Analyst (Rescue Projects)
Jan 2024 - Nov 2025 · 1 year 10 months · Hybrid
Took over at-risk credit risk and data platform projects from departing experts: Oracle SQL redevelopment, data testing concept, source-to-target mapping, data model concept (GCP). Packaging recyclability and carbon footprint workflow for regulatory reporting. Department AI SPOC: AI-assisted delivery, AI tool rollout, colleague training.
Oracle DatabaseGoogle CloudDatabricksMicrosoft Azure
Consultant - Credit Risk Data
Jul 2021 - Dec 2023 · 2 years 5 months
Tier-1 EU Bank
Redevelopment of IRB-based PD/LGD/EAD models for IFRS 9: owned the LGD data stream; structured IFRS 9 flows to mirror IRB for step-by-step comparison; merged operations duplicated across models into one flow. Analytical base tables for PD/EAD/LGD under New DoD; tested implemented logic with QA suites in SAS and SQL.
SASSQL
Senior Financial Analyst, Balance Sheet Reporting & Control
NatWest Markets
May 2019 - Jun 2021 · 2 years 1 month
Owned the Fair Value Level 3 control process: classification checks and validation against transaction data. Balance sheet control from source systems to group consolidation; variance root-cause analysis; automation in SQL, Python, VBA.
SQLPythonVBA