Hi, 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 for:

  • Mobile apps: Kotlin Multiplatform, Android, Flutter
  • Frontend: React, TypeScript
  • Backend: Python, Django, Flask
  • DevOps: Kubernetes, Docker, infrastructure-as-code
  • Architecture consulting

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


2020 – now

IBM: Android/Kotlin lead developer for IBM's electronic health record (ePA) and the CovPass app, security admission (gematik, BSI), end-to-end encryption, homomorphic encryption, multi-party computation, architecture, modernization of the codebase, teaching better development practices. Tech: Coroutines, Jetpack Compose, Kotlin Multiplatform, Ktor, 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