Data engineering
Lakehouse and warehouse pipelines in the cloud: ingestion, transformation, data modelling, testing and data quality.
Szczepan Zieliński IT Solutions
Szczepan Zieliński
Data Engineer · Python Developer
I build data platforms and custom software that organisations rely on every day — from Databricks pipelines for enterprise analytics to complete web systems with PostgreSQL behind them.
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3+ years
of commercial work in Python and SQL
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2 years
of enterprise data engineering at EPAM Systems
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3 certifications
from Databricks and Anthropic
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10+ years
of team leadership in the State Fire Service
What I do
Data engineering and software, end to end
From the data model to deployment and day-to-day maintenance. I care about systems that are tested, documented and still easy to change a year later.
Custom software
Web applications and internal systems built around how a team really works: workflows, permissions, payments, integrations and reporting.
Applied AI
LLM-powered assistants and automation built into real products, and agentic tools used daily to deliver faster without lowering quality.
Experience
Enterprise projects, own products, and a decade of leading people
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2024 — present
Data Engineer · EPAM Systems
Data engineering for international clients on Databricks, Azure and AWS.
- Migration of process-mining analytics to a Databricks Lakehouse for a global consumer-goods company — Medallion pipelines in PySpark and Delta Lake.
- Data quality for a finance BI platform — end-to-end testing of the data warehouse, OLAP cubes and Power BI reports.
- AWS data pipelines for an energy group — a unified customer view for segmentation and churn prediction.
- Data warehouse modelling in PostgreSQL and Power BI dashboards.
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2023 — present
Independent Software Developer
Custom applications for private clients — data model, backend, frontend, deployment and maintenance. Python, Django, Next.js and PostgreSQL.
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10+ years
Shift Commander · State Fire Service (PSP)
Led a firefighting shift in emergency operations: decisions under pressure, responsibility for people, procedures and documentation. It shaped how I approach software — reliability first.
Education: B.Eng. in Fire Safety Engineering, Main School of Fire Service, Warsaw · EPAM Campus — Data Analytics Engineering
Selected work
Systems in daily use
A few projects designed, built and maintained by me — each one in production, with real users.
WCS24 — duty management for fire service units
A multi-tenant SaaS platform for fire stations and district commands: daily duty orders, shift schedules, leave requests with multi-level approval, and working-time records that stay consistent on their own. Built with security in mind — tenant isolation, two-factor authentication, audit logs and automated backups.
Independent commercial product — not an official system of the State Fire Service.
AtHomePsicología — online therapy platform
Public website and back office for a Spanish online psychology practice: client intake, therapist matching, session calendar and payments.
Factura App — invoicing and practice management
A local-first invoicing system with import pipelines from Excel and CSV — matching, deduplication and validation — encrypted data exchange and a Claude-powered assistant.
Guest-room booking system
A public availability calendar with booking requests and a mobile-first staff panel for a public-sector organisation.
Task and procurement tracker
Task and purchase-request tracking for a management team, with priorities, full change history and PDF reports.
Certifications
Verified by the vendors
Databricks
Certified Data Engineer Associate
2026
Databricks
Certified Generative AI Engineer Associate
2026
Anthropic
Claude Certified Architect — Foundations
2026
Full list of courses and certificates on LinkedIn.
Contact
Let's talk
Data engineering, Python development, or a system built for your organisation — send me a message and I will get back to you.