Piotr Zborowski

Piotr Zborowski

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Website: http://piotrzborowski.pl

I am an experienced programmer with over 26 years of professional experience, including more than 15 years of working with Python and 10 years in senior positions. My professional priority is meeting client expectations and delivering top quality solutions. Programming is my passion, bringing me immense satisfaction and motivating me to continually grow and improve. I constantly expand my skill set to implement the latest technologies and best practices in application development. My extensive experience, professional expertise, and determination to achieve excellence enable me to successfully execute even the most demanding projects in the IT industry.

Skills

Backend

Pydantic, SQLAlchemy, Django, Pascal, Delphi, Python, Typer, FastAPI, Python GTK, PHP, Ruby, Grape, Sequel, Flask, Symfony, R, OLE/COM, Merb, Go

Web Development / Frontend

HTML, CSS, jQuery UI, React, Vue.js, Ext JS, Google Maps, Ember.js, JavaScript, Bootstrap, jQuery

AI / LLM

GitHub Copilot, LLM, LangGraph, LangChain, Chainlit, Azure OpenAI, RAG

Other

WebSockets, SSE, Poetry, RabbitMQ, XML, XML Schema, XSLT, Vagrant, SOAP, WSDL, gRPC, Sentry, Logstash, Grafana, MinIO, Apache Parquet, Docker Compose, Locust, ETL, pytest, Apache Airflow, AWS S3, pandas, Docker, GitLab CI/CD, Azure, CI/CD, Elasticsearch, Celery, IIIF, tus, Ansible, Apache Kafka, Excel, PowerPoint, VBA, PDF, Charts, TOML

Architecture & practices

Clean Architecture, Repository Pattern, DI, Event-driven, CQRS, UML, Hexagonal Architecture

Databases

MySQL, Memcached, MongoDB, Oracle, StarRocks, PostgreSQL, SQL, ArangoDB

Experience
Senior Python Developer

Billennium 01.2024 – present

Contracts delivered through Billennium for public sector and healthcare clients.
  • Permissions migration between versions of an e-invoicing system: Python ETL on an Oracle database, incremental loading, zero data loss.
  • Audit log pipeline for data non-repudiation: validators, a MinIO S3 data lake (Parquet), StarRocks.
  • Medical data engineering: anonymisation and validation pipelines in Airflow, in line with GDPR.
  • Conversational AI assistant (RAG) supporting medical device service: LangChain, LangGraph, Azure OpenAI, 7+ languages.

Python, Typer, Hexagonal Architecture, Oracle, MinIO, Apache Parquet, StarRocks, Docker Compose, Locust, ETL, LLM, LangGraph, LangChain, Chainlit, FastAPI, pytest, Azure OpenAI, RAG, PostgreSQL, Apache Airflow, AWS S3, pandas, Docker, GitLab CI/CD, SQL

Senior Python Developer

IThouse 2023

A contract delivered through IThouse for a public sector client: three Django systems, from legacy maintenance to co-designing a new version and migrating its data.
  • Personal data management system in Django and Python GTK with synchronous verification against the PESEL registry.
  • Building decisions register: legacy maintenance (PHP), co-design of the new version's backend (Django, Azure), ETL and migration of all data.
  • Substitute execution notices service (Django, Vue.js): new features, a new interface template, refactoring.

Python, Django, Python GTK, PHP, PostgreSQL, Azure, CI/CD, ETL, Vue.js

Senior Python Developer

eStoremedia 10.2021 – 2023

The company provides consumer product manufacturers with SaaS to maximize e‑commerce sales. It is the only integrated suite of eStore Shelf Analytics, Product Information Management and AI‑based research methodologies.
  • Development of the product information management application.
  • Building integrations with external systems and online stores.
  • Deployment to test and production environments.
  • Researching new solutions, tools and libraries and putting them into use.

Python, Django, PostgreSQL, Elasticsearch, Celery, FastAPI

Senior Python Developer

Britenet 01.2020 – 10.2021

A contract delivered through Britenet for a public sector client.
  • Creation and development of a digital cultural heritage repository.
  • Integration with data from state libraries, museums and archives.
  • Deployment to test environments.
  • Optimizing database queries.
  • Researching new solutions, tools and libraries and putting them into use.

Python, Django, Flask, Docker, PostgreSQL, IIIF, MinIO, tus, Elasticsearch, Celery, ArangoDB

Senior Python Developer

Innovation in IT 03.2016 – 01.2020

A company that creates advanced IT solutions, focusing on increasing the efficiency of business processes - from effectively reaching customers, to multi-dimensional analyzes inspiring new business ideas.
  • As a Python developer, I was responsible for maintaining and enhancing internal CRM and CMS systems for an IT solutions company. My key responsibilities included implementing new features, managing test environment deployments, setting up application monitoring with error tracking, and optimizing database performance. I successfully improved system reliability through automated monitoring solutions and enhanced database efficiency through query optimization, while ensuring seamless operation of business-critical applications.

Python, Django, Ember.js, Docker, Ansible, Apache Kafka

Software Developer

Freelancer – own business 07.2014 – present

Freelance and own project implementation. Creating advanced business applications for various clients, including real estate valuation systems and social panels.
  • As a freelance Python developer, I led the development of diverse business applications, including a real estate valuation platform, a social media management panel, and an application for managing a social panel. My key responsibilities encompassed developing backend functionalities, implementing large-scale data visualization features, building property valuation algorithms, and optimizing database performance. I successfully delivered complex features such as interactive mapping systems, full-text search capabilities, and automated data processing solutions, while maintaining high code quality and system reliability through all project phases.

Ext JS, Ruby, Grape, Sequel, Google Maps, Elasticsearch, Python, Django, JavaScript, Bootstrap, Go, TOML

Software Developer

Team Connect Sp. z o.o. 12.2014 – 06.2015

A company dealing with IT recruitment and outsourcing.
  • Outsourcing for a client from the automotive industry.
  • Development of a search engine with autocomplete and suggestions.

Elasticsearch, Python, Flask, Docker, Docker Compose

Software Developer, IT Manager

Interactive Institute for Market Research IIBR 02.2013 – 11.2014

IIBR company, part of the Gemius SA group. It is the largest company that conducts marketing research via the Internet. The company is now part of the IQS company.
  • As a Python developer at IIBR (part of Gemius SA group, now IQS), I was responsible for developing internal and external software solutions, with a primary focus on creating an online survey system. Key responsibilities included implementing survey functionalities, maintaining research platforms, and mentoring new team members. I successfully delivered robust survey solutions that enhanced the company's market research capabilities while ensuring high system reliability and data accuracy.

Python, Django, jQuery

Software Developer

IPSOS 2005 – 2013

A company that is a part of the international research group Ipsos, present in 84 countries around the world. Specializing in marketing research, advertising, media, consumer satisfaction and loyalty, and opinion research.
  • Developing software for the internal and external needs of the company.
  • Creation of a web data browser.
  • Co-creation of a project management system.

Django, PHP, Symfony, Ruby, jQuery, R, Python, OLE/COM, Excel, PowerPoint, VBA, Merb, Sequel, PDF, Charts, Ext JS

Software Developer/ Sampler

IQS and QUANT Group 2003 – 2005

One of the TOP 10 research agencies in Poland for over 20 years supporting clients in strategic and marketing processes by providing valuable business recommendations.
  • Selection of samples for marketing research.
  • Creation and development of (Delphi) tools for sample selection and processing.
  • Development of software for the company's internal needs, including a research costing system.

Delphi

Sampler/ Software Developer

Millward Brown (formerly SMG/KRC) 2000 – 2003

Millward Brown is a company that carries out marketing research using both traditional and proven methods and the latest achievements of information technology. It has existed since 1990 and is a leader in market and opinion research in Poland and throughout Central and Eastern Europe.
  • Selection of samples for marketing research.
  • Creation and development of tools (Pascal, Delphi) for the selection and processing of samples.
  • Developing software for the internal needs of the company, including the CATI interviewer payroll system.

Pascal, Delphi

Projects
Senior Python Developer

Unified CLI for data pipeline tools

A centralised CLI replacing scripts scattered across the pipelines: ETL, migrations and data catalogue integrations. One command with subcommands called by the pipelines, with tools made interchangeable by a hexagonal architecture.

Python, Typer, Hexagonal Architecture

Senior Python Developer

Audit log pipeline for data non-repudiation

Audit log pipeline built for data non-repudiation. Validators, a MinIO S3 data lake in Parquet and verification queries in StarRocks; blockchain integration prepared as a stub.

Python, Oracle, MinIO, Apache Parquet, StarRocks, Docker Compose, Locust

Senior Python Developer

KSeF 1.0 → 2.0 permissions migration

Data migration of the national e-invoicing system for the Ministry of Finance. Python ETL on Oracle: hundreds of thousands of ZAW-FA permissions moved with zero data loss, with incremental loading.

Python, Oracle, ETL

Senior Python Developer

RDK CoPilot

Conversational AI assistant (RAG) supporting Roche's medical device service. RAG on a vector database, agents in LangChain and LangGraph, recognition of over 4,500 products; the system was in development, tested with users.

Python, LLM, LangGraph, LangChain, Chainlit, FastAPI, pytest, Azure OpenAI, RAG, PostgreSQL

Senior Python Developer

Healthcare Data Processing & Anonymization Pipeline

Pipeline anonymising and validating sensitive medical data in line with GDPR. Airflow DAGs pulling CSV files from S3, anonymisation algorithms and data quality rules with step retries.

Python, Apache Airflow, AWS S3, pandas, Docker, GitLab CI/CD, SQL, pytest

Senior Python Developer

GUNB User Data Management System

User data management system with a desktop client (Python GTK). Synchronous verification against the PESEL registry: whether the person is alive, surname changes, current address; Clean Architecture.

Python, Django, Python GTK

Senior Python Developer

RWDZ – Register of Building Applications, Decisions and Notifications (GUNB)

Register of building applications, decisions and notifications. Legacy maintenance (PHP), co-design of the new version's Django backend on Azure, and ETL migration of all data.

Python, Django, PHP, PostgreSQL, Azure, CI/CD, ETL

Senior Python Developer

eWykonania Zastępcze – substitute execution notices (GUNB)

Substitute execution notices service in Django and Vue.js. Takeover and maintenance, many new features, a new interface template and extensive refactoring.

Python, Django, Vue.js

Ruby Developer

Real Estate Valuation Platform

Real estate database and valuation system with interactive maps. Valuation algorithm logic, map data visualisation and full-text search.

Ext JS, Ruby, Grape, Sequel, Google Maps, Elasticsearch

Senior Python Developer

Product Information Management system

Product information management application. Development of product description features and automatic delivery of product cards to stores.

Python, Django, PostgreSQL, Elasticsearch, Celery, FastAPI

Senior Python Developer

National Repository of Science and Culture Objects

Repository of digital representations of national heritage. Integrations with data from the National Library, the National Museum in Krakow and the National Digital Archives, a knowledge base on a graph database and resumable upload of large files (tus).

Python, Django, Flask, Docker, PostgreSQL, IIIF, MinIO, tus, Elasticsearch, Celery, ArangoDB

Senior Python Developer

Customer relationship management system - CRM

CRM system for a call center and mailing. Maintenance and development, including a module predicting consultant effectiveness.

Python, Django, Ember.js, Docker, Ansible, Apache Kafka

Software Developer

Search with autocomplete and suggestions for Inter Cars

Search engine with autocomplete and suggestions for Inter Cars, built on Elasticsearch.

Elasticsearch, Python, Flask, Docker, Docker Compose

Project Manager/ Developer

Social panel

Application for running a research panel. Communication with panellists and assigning them tasks.

Python, Django, JavaScript, Bootstrap

Lead Developer

Online survey system

System for running online surveys. Respondent selection by quotas and survey fielding: question types, filters, skips, blocks and media.

Python, Django, jQuery

Lead Developer

Project management system

Research project costing and management system.

PHP, Symfony

Project Manager/ Developer

Online reporting application

Web application presenting online research results. Statistical analyses in R.

Ruby, jQuery, R

Project Manager/ Developer

PowerPoint Report Generator

PowerPoint research report generator. Filling templates with data and charts from Excel through OLE.

Python, OLE/COM, Excel, PowerPoint, VBA

Developer

Research project management system

System for research projects run with a network of regional and field coordinators. The whole process, from distributing study information to settling coordinators' invoices; PDF reports and charts.

Ruby, Merb, Sequel, PDF, Charts

Project Manager/ Developer

Kosztorysant – marketing research costing program

Desktop program for costing market research studies. Sample selection algorithm driven by parameters set in the interface.

Delphi

Developer

Simulator Conjoint

Web application simulating the market from conjoint analysis. Comparing scenarios and estimating preference shares from product attribute utilities.

Ruby, Merb, Sequel, Ext JS

Developer

Quota sample solver

CLI program for quota sampling. Quotas and weights of variables and their combinations in a config file, iterative selection minimising deviations, multi-core, quota fulfilment report.

Go, TOML

Other
Course of the Way of the Modern Architect. 2019.
Running a series of Machine Learning (ML) workshops based on TensorFlow. 2018.
Conducting a series of trainings on advanced Excel functions. 2014.
Django course / workshops completed. 2013.
Practical experience with AI copilots and developing solutions based on LLMs, RAG and agentic systems.
Strong expertise in Clean Architecture, SOLID principles, Domain-Driven Design
Experience in code reviews, mentoring, technical leadership
Language
Polish - native
English - reading: fluent, speech: upper-Intermediate
Consents
I consent to the processing of my personal data for the purpose of recruitment in accordance with art. 6 sec. 1 lit. a of the Regulation of the European Parliament and of the Council (EU) 2016/679 of 27 April 2016 on the protection of individuals with regard to the processing of personal data and on the free movement of such data, and repealing Directive 95/46 / EC (general regulation on data protection )