~/balint.decsi

Bálint Décsi

Data Engineer at Deutsche Telekom · CTO at Proximata · Builder at mesh.

Abstract

Engineer focused on the end-to-end data and ML systems lifecycle — from building cloud pipelines and lakehouse platforms to shipping machine-learning solutions with AI agents. Recently graduated from MS in Business Analytics at Central European University. Also love prototyping ML-driven products.

Portrait of Bálint Décsi

† experience‡ github§ linkedin

§1At a glance

Current role
Data Engineer at Deutsche Telekom
Also
CTO at Proximata (Vienna-based hacker lab) · Builder at mesh.
Education
MS Business Analytics, CEU (2025–2026)
Location
Vienna, Austria / Budapest, Hungary

§2Interests & skills

[python][ai agents][ml engineering][apache airflow][apache iceberg][google cloud][deep learning][computer vision][geospatial analytics][xai][sql][data lakehouse][saas prototyping]

§3Work

The work I'd point to first — the venture I'm a co-founder of, plus case studies and demos I've shipped.

§3.1Live

Proximata

Co-founder & CTO — AI-native products lab

Vienna-based hacker lab building AI-native products. I co-founded Proximata and lead technical strategy as CTO — from infrastructure to venture-building and spinoffs.

proximata.io ↗

[ai systems] [venture building] [infrastructure]

§3.2Case studies

MSc capstone — Budapest rental prediction

ingatlan.com × CEU · end-to-end modelling report

Public-facing summary of my MSc Business Analytics capstone: temporal validation, geospatial enrichment (WorldPop + Sentinel-2 NDVI on H3), model leaderboard, SHAP diagnostics, and product recommendations.

read report ↗

[ml] [geospatial] [capstone]

Sovereign data platform

Data Engineer

Turning a 20-year-old telco data estate — full of sensitive customer data and bound by strict EU regulation — into a nimble, cloud-native lakehouse.

  • Apache Iceberg lakehouse on Google Cloud with automated Airflow ingestion for the fixed-line segment.
  • Scalable ML solutions and pipelines delivered through GitLab CI/CD.

google cloud case study ↗

[gcp] [bigquery] [python] [apache iceberg] [airflow] [gitlab ci/cd]

Domestic network optimization

Data Scientist

Greenfield geospatial machine learning for domestic retail-network optimization at Hungary's largest telco and banking companies. A small team covered end-to-end data and ML modelling, from feature store to client presentation.

  • End-to-end delivery of ML models for external B2B clients, on a custom geospatial and location-based feature store.
  • Unsupervised models for network-infrastructure optimization, with Explainable AI (XAI) to build business trust in model decisions.
  • Automated web scraping for competitive intelligence and interactive geospatial visualizations for strategic network planning.

[python] [scikit-learn] [tensorflow] [gis] [bigquery]

Vodafone Hungary data migration

Data Engineer

Moving the data and analytics platform of Hungary's second-largest telco — ~3.8M residential and business subscribers after the UPC Hungary acquisition — to Google Cloud.

  • Built ETL pipelines migrating critical on-premise data to cloud-based environments.
  • Designed and implemented optimized data marts on a cloud-native lakehouse architecture.
  • Worked with cross-functional stakeholders to define technical data requirements.

google cloud case study ↗

[gcp] [bigquery] [sql] [etl] [lakehouse]

§3.3Demos

Comics Factory

ML-driven SaaS for stylized comics with consistent characters

Generate stylized comics with consistent characters from a handful of reference images. Built at Hungary's first hacker space using Supabase, Firebase, and modern image-gen pipelines.

comicsfactory.tech ↗

[llms] [image gen] [saas] [supabase]

CEU FeedForward

Anonymous student-feedback platform for CEU

MVP demo of a secure, GDPR-compliant student feedback platform — registration with a verified @student.ceu.edu email, structured ratings, free-text comments, and institutional dashboards.

open demo ↗

[civic tech] [privacy] [higher ed]

PDF → Word

Convert a PDF to .docx, all in the browser

Drop a PDF in and download an editable .docx. Runs entirely client-side using pdf.js — no file ever leaves your machine.

open tool ↗

[utility] [client-only] [pdf]

Unibridge

Onboarding companion for international students in Vienna

Multi-language prototype that walks new students through housing, health insurance, visa, and local admin. Built as a public-good civic-tech experiment.

open demo ↗

[product] [i18n] [civic tech]

§4Experience

Roles, workplaces, and education — the full CV is downloadable as a PDF.

§4.1Employment

Data Engineer

Deutsche Telekom IT Solutions HU · May 2024 — Present · Budapest, Hungary

  • Engineering scalable ML solutions and pipelines for the fixed-line business segment.
  • Building a modern Data Lakehouse using Apache Iceberg on Google Cloud Platform.
  • Developing automated Apache Airflow pipelines for robust data ingestion and processing.

[ml engineering][apache iceberg][gcp][airflow][data lakehouse]

CTO

Proximata · May 2026 — Present · Vienna, Austria

  • Leading technical strategy and execution at Proximata, a Vienna-based hacker lab.
  • Driving product and engineering decisions from concept to production for AI-native products.
  • Building tech solutions and spinoffs by enabling ambitious builders with infrastructure and resources.

[technical leadership][ai systems][product engineering][venture building]

Builder

mesh. · June 2025 — Present · Budapest, Hungary

  • Member of Hungary's first hacker space.
  • Engineering an ML-driven SaaS that generates stylized comics with consistent characters from images.
  • Rapid prototyping using Supabase, Firebase, and modern full-stack tools.
  • Leveraging AI agents (Cursor, Gemini CLI, Copilot) for accelerated, parallelized development.

[ai agents][ml prototyping][saas][supabase][firebase][llms]

Advanced Analytics Expert

Vodafone Hungary · Oct 2023 — Apr 2024 · Budapest, Hungary

  • Optimizing network infrastructure using unsupervised machine learning techniques.
  • Implementing Explainable AI (XAI) to drive business engagement and trust in model decisions.
  • Developing interactive geospatial visualizations to support strategic network planning.

[unsupervised ml][xai][geospatial][python]

Data Scientist

Vodafone Hungary · Apr 2023 — Oct 2023 · Budapest, Hungary

  • Fourth rotation in Vodafone's Discover Graduate Program.
  • End-to-end delivery of machine learning models for external B2B clients.
  • Engineered a custom feature store for geospatial and location-based data.
  • Developed automated web scraping tools for competitive intelligence gathering.

[ml modeling][python][feature engineering][web scraping][geospatial]

Data Analyst

Vodafone Hungary · Oct 2022 — Apr 2023 · Budapest, Hungary

  • Third rotation in Vodafone's Discover Graduate Program.
  • Architected foundation data models for a major geospatial retail analytics initiative.
  • Translated complex analytical results into actionable reports for business stakeholders.

[sql][data visualization][bi][geospatial]

Data Warehouse Specialist

Vodafone Hungary · Apr 2022 — Oct 2022 · Budapest, Hungary

  • Second rotation in Vodafone's Discover Graduate Program.
  • Designed and implemented optimized data marts on a cloud-native lakehouse architecture.
  • Collaborated with cross-functional stakeholders to define technical data requirements.

[cloud dwh][sql][data modeling][lakehouse]

Data Engineer

Vodafone Hungary · Sep 2021 — Apr 2022 · Budapest, Hungary

  • First rotation in Vodafone's Discover Graduate Program.
  • Built ETL pipelines migrating critical on-premise data to cloud-based environments.

[data pipelines][cloud migration][etl]

Undergraduate Research Fellow

Institute of Biochemistry, Biological Research Centre · Jan 2019 — Jun 2020 · Szeged, Hungary

  • Developed computer vision plugins for automated biological image analysis.
  • Applied deep learning techniques to high-throughput microscopy data.
  • Designed and implemented robust data management systems for large-scale measurements.

[computer vision][deep learning][biomedical imaging]

§4.2Education

MS Business Analytics

Central European University · Sep 2025 — Jun 2026

MS Data Science for Machine Learning

Pázmány Péter Catholic University · Jan 2020 — Dec 2021

BS Molecular Bionics

University of Szeged · 2016 — 2020

Exchange — Biomedical Engineering

Universidad CES, Colombia · 2019

§5Certifications & awards

Credentials, badges, and scholarships — each links to the issuing authority where available.

§5.1Certifications

§5.2Awards & scholarships

  • Highlighted Study Scholarship of the Hungarian State
  • Municipal Scholarship of Szeged
  • Campus Mundi Scholarship
  • IT Star Award
  • Data Rockstar

§6Code

Repositories and side projects — what I've built, shipped, and open-sourced.

§6.1Side projects

Comics Factory

ML-driven SaaS that generates stylized comics with consistent characters from a handful of reference images. Built at Hungary's first hacker space using Supabase, Firebase, and modern image-gen pipelines.

[llms][image gen][saas][supabase]

comicsfactory.tech · growmesh.io

§6.2Theses

§6.3Open source & experiments

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