Senior Backend Developer & Software Engineer Python, SQL, NoSQL, REST, Cloud, ML, AI, LLMs
Aktualisiert am 28.11.2025
Profil
Freiberufler / Selbstständiger
Remote-Arbeit
Verfügbar ab: 01.12.2025
Verfügbar zu: 100%
davon vor Ort: 100%
Python
Postgres Plus
Machine Learning
Back-End
Haskell
SQL
NoSQL
REST
Cloud
AWS
Künstliche Intelligenz
Deep Learning
German
Muttersprache
English
near-native level

Einsatzorte

Einsatzorte

Berlin (+50km) Hamburg (+50km) Kiel (+50km)
Deutschland
möglich

Projekte

Projekte

10 months
2024-02 - 2024-11

Designed and implemented RESTful APIs

PostgreSQL backend developer Docker Git Jira ...
PostgreSQL backend developer
  • Rewrite of the mytischtennis website with an high-performance database-first backend written in PostgreSQL and PL/pgSQL.
  • Creation of payment and order workflows integrating PayPal and PayOne as payment providers.
  • Retrieval of data from external systems using Postgres caching for fast access times.
  • Designed and implemented RESTful APIs for communication with frontend and external tools
Docker Git Jira PostgreSQL PL/pgSQL PLV8/JavaScript/V8 Scrum Supabase Supabase Storage (AWS S3-compatible)
ACB Studio
Düsseldorf, remote
9 months
2023-04 - 2023-12

Development of SPACE

Python/Pandas developer and data scientist Apache Spark Camunda Databricks ...
Python/Pandas developer and data scientist
  • Development of SPACE (Statistical Production and Compilation Environment), the new data analytics platform used by the European Central Bank (ECB).
  • Integration of various data sources from banks and statistical authorities into the ECB?s new Pandas-based data analytics platform.
  • Cloud integration via Cloudera Hadoop
  • Analysis and elimination of performance bottlenecks in the software.
  • Porting of the whole SPACE software from Pandas 1.3 to 2.1.
Apache Spark Camunda Databricks Docker/Kubernetes/Helm REST APIs with FastAPI Git Jira JupyterHub Kerberos Numpy Pandas Pydantic Pytest PyTorch Scrum
T-Systems International
Frankfurt, remote
6 years 11 months
2016-05 - 2023-03

Independent research project:

Flask Gunicorn lxml ...
  • Independent research project: Computational/linguistic support for easier international communication
  • Designed Lytspel, a proposal for an easier and more logical English spelling, and created an online converter and website for it: (URL on request)
  • Shortlisted as one of the best proposals by the International English Spelling Congress held by the English Spelling Society in early 2021.
  • Contributing to websites and online dictionaries of the international auxiliary languages Lingua Franca Nova (Elefen) and Esperanto.
  • Started Lugamun, another auxiliary languages with a more global vocabulary and a computer-supported word selection process, and created a website for it: (URL on request)
  • Gave a talk about Lugamun at the annual conference of the Society for Interlinguistics (Nov. 2022) and published a paper in their annual proceedings (Jahrbuch der Gesellschaft für Interlinguistik 2023).
Flask Gunicorn lxml spaCy Bootstrap jQuery
7 months
2022-05 - 2022-11

Integration of file-upload functionality to third-party platforms

Python and Ruby developer AWS/Boto3 Docker Flask ...
Python and Ruby developer
  • Creation of a RESTful cloud-based document classification microservice.
  • Prototype system for extraction of structured data from scanned forms (RESTful microservice).
AWS/Boto3 Docker Flask Git microservices with REST API NumPy Paperless-ngx PIL Pytest Ruby on Rails RSpec scikit-learn Tesseract OCR
Dropscan GmbH
Berlin, remote
2 months
2022-06 - 2022-07

Wire messenger

Haskell developer GHC Git Stack ...
Haskell developer
  • Integration of HTTP 2 support to HsOpenSSL
  • Debugging of issues with binary frame data exchange?

GHC Git Stack Wireshark
Zeta Project Germany/Wire Swiss GmbH,
Berlin, remote
1 year 5 months
2016-02 - 2017-06

various Projects

Paid researcher
Paid researcher
  • Member of the interdisciplinary project (on request)
  • Jointly wrote and produced the book Society After Money: (on request)
  • Co-organized and participated in several related work-shops.
University of Bonn
11 years 1 month
2005-12 - 2016-12

Independent research project

  • Independent research project ?Commons and peer production as modes of economic cooperation?
  • Published From Exchange to Contributions (on request), also published in German as Beitragen statt tauschen (on request).
  • Also published various articles and gave multiple talks.
  • Cofounder, author, and admin of the (on request)
  • Member of the (on request)
1 year 11 months
2014-03 - 2016-01

Adhocracy 3 platform

Python and Haskell developer PostgreSQL Pyramid Flake8 ...
Python and Haskell developer
  • Design and implementation of a REST API for backend/frontend communication.
  • Added support for various functionalities using user registration and login, capchas, email verification, comment editing and version management, image upload, websocket service for notifications, search service.
PostgreSQL Pyramid Flake8 Pytest Scrum GHC Cabal
Liquid Democracy
Berlin
1 year 7 months
2012-02 - 2013-08

Added functionality to the in-house Java framework

Java backend developer Git Icinga Jenkins ...
Java backend developer
  • Extended the used PostgreSQL DB, using JDBC and stored procedures to access it.
  • Java and SQL profiling and optimization.
  • Created and integrated an search service based on Apache Solr.
  • Designed and implemented a RESTful API for communication with the frontend.
  • Designed a markup language for ad templates and a parser for it.
Git Icinga Jenkins Maven Scrum Spread Spring Tomcat
Project A and DeltaMethod
Berlin
10 months
2011-02 - 2011-11

Several startups founded by Rocket

Java backend developer Basecamp Ehcache Jenkins ...
Java backend developer
  • Designed, implemented, and tested new functionality.
  • Extended the PostgreSQL DB using stored procedures.
  • Created and integrated an search service based on Apache Solr, including support for multiple languages and master-slave replication.
  • Integrated the Couchbase Server NoSQL DB for in-memory caching.
  • Designed and implemented a queue-based update ser4 vice for Solr and Couchbase that prevents data loss in case of server failures.
  • Profiled and optimized performance bottlenecks.
Basecamp Ehcache Jenkins Maven Nagios Scrum Spread Spring Tomcat
Rocket Internet
Berlin
5 months
2010-06 - 2010-10

Designed, implemented, and tested new functionality

Java backend developer Ehcache Maven Nagios ...
Java backend developer
  • Designed, implemented, and tested new functionality using Java and SQL/PostgreSQL.
  • Implemented order handling workflow (received, paid, shipped etc.).
  • Interaction workflows with payment providers and fulfillment partners.
  • Designed and implemented a RESTful microservices for communication with the frontend and other components.
  • Created a Solr-based search service for article management in the backend.
  • Creating a Spread-based messaging service for synchronizing categories, attributes etc. across instances.
Ehcache Maven Nagios Spread Spring Tomcat
Zalando
Berlin
10 months
2008-09 - 2009-06

Software design, development, and testing

Python backend developer Mercurial NumPy PyMC ...
Python backend developer
  • Software design, development, and testing in Python.
  • Integration of NumPy, SciPy, and PyMC for Bayesian statistical modeling and analysis.?

Mercurial NumPy PyMC SciPy Trac
BART (?Bayesian Analysis & Reporting Tool?), an EXIST-founded university-based start-up at the Free University of Berlin
Berlin
1 year 3 months
2006-12 - 2008-02

Designed and led the implementation of a prototype system

Machine learning specialist and Java backend programmer Hibernate MySQL TreeTagger
Machine learning specialist and Java backend programmer
  • Researched and documented the state of the art in sentiment analysis.
  • Designed and led the implementation of a prototype system for sentiment analysis that distinguishes positive, negative, and neutral statements in product review.
  • Document management and text extraction from HTML and PDF files; integrated linguistic tools for sentence splitting and POS tagging.
  • Prototyped a heuristic and trainable system for identifying products and product properties described in sentences.
  • Created a trainable sentence classifier based on the system developed for my PhD thesis.
Hibernate MySQL TreeTagger
Producto
Berlin
2 years 3 months
2001-05 - 2003-07

Mundwerk VoiceXML Platform

Java developer
Java developer

Mundwerk AG
Berlin
8 months
2000-08 - 2001-03

various Projects

Java developer
Java developer
WorldOS Corp.

Aus- und Weiterbildung

Aus- und Weiterbildung

2003 - 02/ 2007

PhD in Computer Science

Free University of Berlin

?
Key Focus:

  • Thesis title: on request
  • Thesis topic: on request


1996 - 03/ 2002

Diplom Studies Computer Science

Diplom-Informatiker (Master of Science in Computer Science)

Technical University of Berlin

?

Key Focus:

  • Thesis title: on request
  • Thesis topic: on request

Position

Position

  • Senior Backend Developer
  • Software Engineer

Kompetenzen

Kompetenzen

Top-Skills

Python Postgres Plus Machine Learning Back-End Haskell SQL NoSQL REST Cloud AWS Künstliche Intelligenz Deep Learning

Produkte / Standards / Erfahrungen / Methoden

Profile

  • PhD in Computer Science (machine learning).
  • Freelancing since 2006.
  • Experience with statistical machine learning (artificial intelligence) since my Diplom thesis in 2001/2002.
  • Focus on backend web development, database and search server integration, statistical machine learning, cloud computing (esp. AWS), REST APIs, microservices.
  • Proficient in Python, Ruby, Haskell, Java, JavaScript, SQL/stored procedures.
  • Experienced with agile development/Scrum, test-driven development, refactoring, profiling/optimization.

Einsatzorte

Einsatzorte

Berlin (+50km) Hamburg (+50km) Kiel (+50km)
Deutschland
möglich

Projekte

Projekte

10 months
2024-02 - 2024-11

Designed and implemented RESTful APIs

PostgreSQL backend developer Docker Git Jira ...
PostgreSQL backend developer
  • Rewrite of the mytischtennis website with an high-performance database-first backend written in PostgreSQL and PL/pgSQL.
  • Creation of payment and order workflows integrating PayPal and PayOne as payment providers.
  • Retrieval of data from external systems using Postgres caching for fast access times.
  • Designed and implemented RESTful APIs for communication with frontend and external tools
Docker Git Jira PostgreSQL PL/pgSQL PLV8/JavaScript/V8 Scrum Supabase Supabase Storage (AWS S3-compatible)
ACB Studio
Düsseldorf, remote
9 months
2023-04 - 2023-12

Development of SPACE

Python/Pandas developer and data scientist Apache Spark Camunda Databricks ...
Python/Pandas developer and data scientist
  • Development of SPACE (Statistical Production and Compilation Environment), the new data analytics platform used by the European Central Bank (ECB).
  • Integration of various data sources from banks and statistical authorities into the ECB?s new Pandas-based data analytics platform.
  • Cloud integration via Cloudera Hadoop
  • Analysis and elimination of performance bottlenecks in the software.
  • Porting of the whole SPACE software from Pandas 1.3 to 2.1.
Apache Spark Camunda Databricks Docker/Kubernetes/Helm REST APIs with FastAPI Git Jira JupyterHub Kerberos Numpy Pandas Pydantic Pytest PyTorch Scrum
T-Systems International
Frankfurt, remote
6 years 11 months
2016-05 - 2023-03

Independent research project:

Flask Gunicorn lxml ...
  • Independent research project: Computational/linguistic support for easier international communication
  • Designed Lytspel, a proposal for an easier and more logical English spelling, and created an online converter and website for it: (URL on request)
  • Shortlisted as one of the best proposals by the International English Spelling Congress held by the English Spelling Society in early 2021.
  • Contributing to websites and online dictionaries of the international auxiliary languages Lingua Franca Nova (Elefen) and Esperanto.
  • Started Lugamun, another auxiliary languages with a more global vocabulary and a computer-supported word selection process, and created a website for it: (URL on request)
  • Gave a talk about Lugamun at the annual conference of the Society for Interlinguistics (Nov. 2022) and published a paper in their annual proceedings (Jahrbuch der Gesellschaft für Interlinguistik 2023).
Flask Gunicorn lxml spaCy Bootstrap jQuery
7 months
2022-05 - 2022-11

Integration of file-upload functionality to third-party platforms

Python and Ruby developer AWS/Boto3 Docker Flask ...
Python and Ruby developer
  • Creation of a RESTful cloud-based document classification microservice.
  • Prototype system for extraction of structured data from scanned forms (RESTful microservice).
AWS/Boto3 Docker Flask Git microservices with REST API NumPy Paperless-ngx PIL Pytest Ruby on Rails RSpec scikit-learn Tesseract OCR
Dropscan GmbH
Berlin, remote
2 months
2022-06 - 2022-07

Wire messenger

Haskell developer GHC Git Stack ...
Haskell developer
  • Integration of HTTP 2 support to HsOpenSSL
  • Debugging of issues with binary frame data exchange?

GHC Git Stack Wireshark
Zeta Project Germany/Wire Swiss GmbH,
Berlin, remote
1 year 5 months
2016-02 - 2017-06

various Projects

Paid researcher
Paid researcher
  • Member of the interdisciplinary project (on request)
  • Jointly wrote and produced the book Society After Money: (on request)
  • Co-organized and participated in several related work-shops.
University of Bonn
11 years 1 month
2005-12 - 2016-12

Independent research project

  • Independent research project ?Commons and peer production as modes of economic cooperation?
  • Published From Exchange to Contributions (on request), also published in German as Beitragen statt tauschen (on request).
  • Also published various articles and gave multiple talks.
  • Cofounder, author, and admin of the (on request)
  • Member of the (on request)
1 year 11 months
2014-03 - 2016-01

Adhocracy 3 platform

Python and Haskell developer PostgreSQL Pyramid Flake8 ...
Python and Haskell developer
  • Design and implementation of a REST API for backend/frontend communication.
  • Added support for various functionalities using user registration and login, capchas, email verification, comment editing and version management, image upload, websocket service for notifications, search service.
PostgreSQL Pyramid Flake8 Pytest Scrum GHC Cabal
Liquid Democracy
Berlin
1 year 7 months
2012-02 - 2013-08

Added functionality to the in-house Java framework

Java backend developer Git Icinga Jenkins ...
Java backend developer
  • Extended the used PostgreSQL DB, using JDBC and stored procedures to access it.
  • Java and SQL profiling and optimization.
  • Created and integrated an search service based on Apache Solr.
  • Designed and implemented a RESTful API for communication with the frontend.
  • Designed a markup language for ad templates and a parser for it.
Git Icinga Jenkins Maven Scrum Spread Spring Tomcat
Project A and DeltaMethod
Berlin
10 months
2011-02 - 2011-11

Several startups founded by Rocket

Java backend developer Basecamp Ehcache Jenkins ...
Java backend developer
  • Designed, implemented, and tested new functionality.
  • Extended the PostgreSQL DB using stored procedures.
  • Created and integrated an search service based on Apache Solr, including support for multiple languages and master-slave replication.
  • Integrated the Couchbase Server NoSQL DB for in-memory caching.
  • Designed and implemented a queue-based update ser4 vice for Solr and Couchbase that prevents data loss in case of server failures.
  • Profiled and optimized performance bottlenecks.
Basecamp Ehcache Jenkins Maven Nagios Scrum Spread Spring Tomcat
Rocket Internet
Berlin
5 months
2010-06 - 2010-10

Designed, implemented, and tested new functionality

Java backend developer Ehcache Maven Nagios ...
Java backend developer
  • Designed, implemented, and tested new functionality using Java and SQL/PostgreSQL.
  • Implemented order handling workflow (received, paid, shipped etc.).
  • Interaction workflows with payment providers and fulfillment partners.
  • Designed and implemented a RESTful microservices for communication with the frontend and other components.
  • Created a Solr-based search service for article management in the backend.
  • Creating a Spread-based messaging service for synchronizing categories, attributes etc. across instances.
Ehcache Maven Nagios Spread Spring Tomcat
Zalando
Berlin
10 months
2008-09 - 2009-06

Software design, development, and testing

Python backend developer Mercurial NumPy PyMC ...
Python backend developer
  • Software design, development, and testing in Python.
  • Integration of NumPy, SciPy, and PyMC for Bayesian statistical modeling and analysis.?

Mercurial NumPy PyMC SciPy Trac
BART (?Bayesian Analysis & Reporting Tool?), an EXIST-founded university-based start-up at the Free University of Berlin
Berlin
1 year 3 months
2006-12 - 2008-02

Designed and led the implementation of a prototype system

Machine learning specialist and Java backend programmer Hibernate MySQL TreeTagger
Machine learning specialist and Java backend programmer
  • Researched and documented the state of the art in sentiment analysis.
  • Designed and led the implementation of a prototype system for sentiment analysis that distinguishes positive, negative, and neutral statements in product review.
  • Document management and text extraction from HTML and PDF files; integrated linguistic tools for sentence splitting and POS tagging.
  • Prototyped a heuristic and trainable system for identifying products and product properties described in sentences.
  • Created a trainable sentence classifier based on the system developed for my PhD thesis.
Hibernate MySQL TreeTagger
Producto
Berlin
2 years 3 months
2001-05 - 2003-07

Mundwerk VoiceXML Platform

Java developer
Java developer

Mundwerk AG
Berlin
8 months
2000-08 - 2001-03

various Projects

Java developer
Java developer
WorldOS Corp.

Aus- und Weiterbildung

Aus- und Weiterbildung

2003 - 02/ 2007

PhD in Computer Science

Free University of Berlin

?
Key Focus:

  • Thesis title: on request
  • Thesis topic: on request


1996 - 03/ 2002

Diplom Studies Computer Science

Diplom-Informatiker (Master of Science in Computer Science)

Technical University of Berlin

?

Key Focus:

  • Thesis title: on request
  • Thesis topic: on request

Position

Position

  • Senior Backend Developer
  • Software Engineer

Kompetenzen

Kompetenzen

Top-Skills

Python Postgres Plus Machine Learning Back-End Haskell SQL NoSQL REST Cloud AWS Künstliche Intelligenz Deep Learning

Produkte / Standards / Erfahrungen / Methoden

Profile

  • PhD in Computer Science (machine learning).
  • Freelancing since 2006.
  • Experience with statistical machine learning (artificial intelligence) since my Diplom thesis in 2001/2002.
  • Focus on backend web development, database and search server integration, statistical machine learning, cloud computing (esp. AWS), REST APIs, microservices.
  • Proficient in Python, Ruby, Haskell, Java, JavaScript, SQL/stored procedures.
  • Experienced with agile development/Scrum, test-driven development, refactoring, profiling/optimization.

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