Felix Uellendall

Data Engineer, Open Source Enthusiast and Apache Airflow Committer

About Me

Hi, my name is Felix Uellendall. I am a young Data Engineer working in a data team for a digital agency in Berlin, Germany. I joined the Apache Software Foundation in September 2019. Since then I am also an Apache Airflow Committer.

Technical Skills

I am most skilled in:

Apache Airflow Python Unit Testing

I have experience in:

Agile Methodologies Amazon Redshift AWS Bash C# CI/CD CSS dbt Docker ETL/ELT Git great_expectations HTML Java JavaScript MySQL PostgreSQL Python Pandas REST Software Design Software Development System Testing

I am familiar with:

Apache Spark Databricks Express.js GCP Golang Julialang Kubernetes Microsoft Azure Node.js Terraform Test Driven Development


German (Native speaker) and English (Upper-intermediate)


"Airflow is a platform to programmatically author, schedule and monitor workflows." - Apache Airflow

In search for a solution for the management of data pipelines I stumbled upon the Open-Source project Apache Airflow in January 2018. I really appreciate the simplicity of use, high coverage of use cases and the community behind it. That’s why I decided to give something back so I started contributing and am now a committer of this project.

"Auto-generated Diagrams from Airflow DAGs." - Felix Uellendall

A personal project to auto-generate diagrams based on Apache Airflow DAGs. Airflow DAGs specify workflows which consists of tasks which can depend on eachother. Based of these tasks and dependencies a Diagram will be generated. A Diagram visualises the provider (often cloud-based) used in the Airflow DAGs by simply displaying its logos.

"An Airflow plugin to visualise airflow-diagrams." - Felix Uellendall

A personal project to easily integrate airflow-diagrams to Apache Airflow. An Airflow Plugin can be easily added to a Apache Airflow installation and in this case visualises the output of airflow-diagrams.

"A database and api service for movies hosted on a dockerized raspberry pi." - Felix Uellendall

A personal project for user-friendly self hosting of an API Service on simple computer devices.

"An analytics stack on a raspberry pi deployed in kubernetes." - Felix Uellendall

A personal project for user-friendly self hosting of an analytics stack on simple computer devices.


Apache Software Foundation


Apache Airflow Committer

September 2019 - Present

"The World's Largest Open Source Foundation" - Apache Software Foundation

For Apache Airflow I am..

  • writing project and code documentation
  • writing unit tests in python
  • adding new features like Airflow hooks and operators
  • reporting bugs via Jira or GitHub Issues
  • communicating with the community via email and slack
  • writing Airflow Improvement Proposals in Confluence
  • reviewing GitHub pull requests
  • helping users to join the community
  • testing and voting releases

Digitas Pixelpark GmbH


Junior Data Engineer

January 2018 - Present

"Germany's most impactful customer experience agency" - Digitas Pixelpark GmbH

  • built a data management platform on AWS for our data analysts and scientists to access analytics data efficiently
  • added CI/CD to our DMP (data management platform) via GitLab CI/CD which lints, tests, builds documentation and deploys our code to a development or production environment
  • building (ETL/ELT) data pipelines with Apache Airflow
  • connecting new data sources (mostly via REST APIs) to our data platform
  • transforming data via SQL or Python Pandas to be analytics-ready
  • designing workflows efficiently by making use of a lot of features of Apache Airflow
  • monitoring of our data pipelines

NETRONIC Software GmbH


Student Research Assistant

August 2012 - August 2016

"Our mission is to enable every SMB organization to achieve operational agility with visual scheduling." - NETRONIC Software GmbH

  • built a .NET Windows Forms application in C#
  • learned that code readibility is important through refactoring and mentorship
  • learned the efficient usage of version control systems
  • built a web application accessing Microsoft Azure Active Directoy via a REST API to manage users for one of our products
  • built a hybrid mobile application to let our customers monitor their machines status easily




Shortened apprenticeship for software development

September 2016 - January 2018

Oberstufenzentrum Informations- und Medizintechnik

During my time of the apprentice I was working for Publicis Pixelpark GmbH. There I built..

  • a REST API with the Spring Framework in Java
  • a web application with Node.js, Express.js and Handlebars
  • a command line application for our data team for automated transfer of social listening data

FH Aachen


ICT with specifics in application development [Incomplete]

August 2013 - August 2016

Aachen University of Applied Sciences

I learned about..

  • the basics of programming in C++
  • several other programming languages like Assembly, Prolog and Matlab
  • algorithms and data structures
  • IT security and forensic
  • databases and web technologies
  • computer systems architectures, operating systems and distributed systems

Bk GuT


IT assistant and advanced technical college entrance qualification

August 2010 - August 2013

Berufskolleg für Gestaltung und Technik

I learned about..

  • the basics of programming in C# and Java
  • web development with PHP and MySQL

A Little More About Me

I love creating things, solving puzzles, thinking about code and improving challenging problems. Open Source is what I like doing the most. I enjoy working in the community and sharing my knowledge with each other.

I also fell in love with the nature and the silence being out there. I like hiking, playing the piano and I am fascinated by the universe.