Jakub Lejk

Ruda Slaska, Poland· (+48) 510-823-879 · jakub@lejk.net

I’m an experienced Business Intelligence Analyst specializing in end-to-end data solutions. My expertise spans the entire data life cycle - from setting up servers and databases, through data extraction, transformation, and modeling, to building insightful reports and visualizations. In addition to my BI work, I also provide freelance services in web scraping, data transformation, API integration, and web application development.

Experience

Business Intelligence Specialist

Deutsche Bahn CARGO POLAND

At DB Cargo, I am responsible for extracting data from various systems, including several legacy platforms that require special attention when automating data extraction processes. I transform this data using technologies such as Tableau Prep and Python (with libraries like Pandas and PySpark).

A key part of my role involves delivering insights to the executive board by generating reports on critical KPIs—such as the volume of cargo transported over specific periods, total kilometers covered by our locomotives, and the monthly working hours of our locomotive drivers and railway auditors.

I'm also responsible for developing an application that generates work schedules for over 600 employees involved in railway operations. In addition, I assist with setting up SharePoint spaces and contribute to internal tool development through Power Automate and Power Apps integration.

February 2024 - Present

Tax Technology Associate

PricewaterhouseCoopers SDC POLAND

I was a part of an international technology team focused on migrating global clients to a new data architecture. I was responsible for setting up environments and building workflows to upload and parse transactional data, using tools such as Groovy, Google Workspace, VBA, and Alteryx.

May 2023 - February 2024

Category Management Department Appretice

Aldi Poland

I was an apprentice in the Category Management Department at Aldi, where I used VBA and Power BI to identify missing records and ensure accurate data entry into the SAP system. I also contributed to creating planograms—visual layouts that determine optimal product placement in stores to maximize efficiency and sales.

July 2022 - September 2022

Education

University of Economics in Katowice

Masters of Computer Science and Econometry

Rector's Scholarship holder

GPA: 4.43 / 5.0 (Polish grading system)

October 2023 - July 2025

University of Economics in Katowice

Bachelors of Economy

Rector's Scholarship holder

Specialization: Digital Economy

GPA: 4.5 / 5.0 (Polish grading system)

October 2020 - July 2023

Skills

Programming Languages & Tools

Microsoft Stack

Interests

Outside of work, I find joy in spending time in nature. My favorite activities include running, hiking in the mountains, and taking long walks with my dog Fokus—often with an ice cream in hand.

When I’m indoors, I like tinkering with my self-hosted server, writing scripts for home automation, and building web scrapers for fun and experimentation. I’m always curious about how things work and enjoy exploring new ways to automate the world around me.

Fokus

Certifications

ING Hubs - Microsoft SQL Server
Issued: June 2025

Certification ID: 7f9a9882-de15-4712-ae90-db42bfb2a655
Microsoft Certified: Fabric Data Engineer Associate
Issued: June 2025

Certification ID: F0FEC069C37142B7
Microsoft Certified: Azure Data Engineer Associate
Issued: March 2025

Certification ID: 5898B24D4C34CA5D
Microsoft Certified: Azure Data Fundamentals
Issued: January 2025

Certification ID: C2E9E4A959E2CEA4
Microsoft Certified: Azure Fundamentals
Issued: November 2024

Certification ID: 7F1E74CFEFEF4849
Tableau Fundamentals
Issued: January 2024

Certification ID: gw5vca4p4syt
Japanese Language Proficiency Test - N3 Level
Issued: January 2024

Certification ID: N3A438419A
Certificate in ESOL International (Listening, Reading, Test of English C2)
Issued: April 2021

Certification ID: GR908001440JL

Projects

Business Info Poland

A Web application that allows user to search for company based in Poland, in order to recieve detailed information about business and to bulk-downlaod business statements of this company

Business Data API

Backend API responsible for scraping, transforming and storing data about businesses, so they can be later served to the Business Info Poland Web App

Docker Compose for PostgreSQL + Kafka

Out-of-the-box docker compose file, with predefined settings that add streaming capability to PostgreSQL DB. New records can be ingested, for example, by Spark Streaming Service

Docker Compose for Grafana + Prometheus Stack

Project that simplifies setting up Grafana + Prometheus. Has in-build support for Cadvisor exporter (docker image logs) and node exporter (sys logs)

Docker Compose for SPARK

This project allows for setting up Spark clusters on your local machines. Docker images install all necessary dependecies, such as Java and PySpark, so the user just builds the stack with makefile, without any dependency management.

Freelance Services

I offer freelance services focused on data extraction, transformation, and delivery. If you’re looking for custom solutions to automate data collection or need structured, accessible datasets, I can help.

Web scraping jobs tailored to your industry or platform.
Data transformation and structuring into usable formats.
Delivery via CSV, database sharing, or API endpoints.
Development of REST APIs and web apps to access and share your data.

If you’re interested in working together, feel free to reach out via email — I’d be happy to discuss your project needs!