I'm Waldemar Kornewald - a freelance software engineer based in Hamburg, Germany. If you have complex code/bugs and need help designing easy to understand, maintainable code that prevents commonly recurring problems, please get in touch.

I'm available remote world-wide or on-site in Hamburg and my current primary focus is on Kotlin Multiplatform and Android development and architecture consulting. In the past I've also worked for many years with Python, Django, TypeScript, React, Flutter, Kubernetes and other technologies, so I have a broad experience profile.

If you need help with one of your projects just contact me: hello@ensody.com


2020 – now

IBM: Android/Kotlin Multiplatform lead developer for IBM's electronic health record (ePA) and the CovPass app, security admission (gematik, BSI), architecture & modernization of the codebase, end-to-end encryption, homomorphic encryption, multi-party computation, FHIR, code generators, custom parsers, teaching better development practices. Tech: Kotlin Multiplatform, Jetpack Compose, Ktor, coroutines, kotlin.test, MockK, etc.

2017 – 2020

Ovy: Flutter, Android/Kotlin/Java, Flask/Python, Bluetooth LE (custom thermometer), Dockerized dev env, Google App Engine, Redis

2017 – 2017

SPIEGEL: Kubernetes setup/ops (on-prem & GKE), how-to-use workshops, Elasticsearch, PostgreSQL, Prometheus, Kibana, Grafana, Docker images for various services, etc.

2014 – 2020

Locandis: Android/Kotlin/Java, React/TypeScript/JavaScript, Django/Python, Bluetooth LE (iBeacons), PostgreSQL, Redis, Docker

2015 – 2018

sefibo: React/TypeScript/JavaScript, Django/Python, Elasticsearch, PostgreSQL, Redis, Docker, custom task queue

2014 – 2015

Mainmetrics: Django/Python/SQLAlchemy, Python/JavaScript frontend, PostgreSQL, Redis, Docker

2008 – 2014

various customers: Python, JavaScript, Django, Android, Java, Google App Engine, PostgreSQL, MySQL, Elasticsearch, MongoDB, Redis, C++

1999 – 2008

various open-source projects: Python, Django, Trac, C++, Java, GPIB, WinAPI, Perl, PHP, x86 asm, USB HID

Open-source by Ensody®

Over the past 20 years I've also made several open-source contributions:

  • ReactiveState-Kotlin: Easy reactive state management for Kotlin Multiplatform. No boilerplate. Compatible with Android.
  • github/ensody
  • github/wkornewald
  • Django-nonrel: Fork of the Django web framework adding NoSQL support to its ORM (including backends for App Engine Datastore, Elasticsearch, MongoDB, etc.)
  • github/allbuttonspressed
  • Haiku: An open-source operating system project where I worked on PPP(oE) network protocols in the kernel, network settings app, website, Trac extensions/customizations, etc.
  • PyMeta 2: Parsing Expression Grammar (PEG) based on OMeta 2.
  • PyvaScript: Simple Python-inspired programming language that transpiles to JS. Implemented with PyMeta 2 (parsing raw text).
  • py2gpu: Python -> CUDA compiler. Implemented with PyMeta 2 (parsing the tree structure generated by Python's ast module).
  • pyjs: Optimizing, optionally typed Python -> JavaScript transpiler.
  • bitbucket/wkornewald