Kai Koehn, Developer in Den Haag, Netherlands
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Kai Koehn

Verified Expert  in Engineering

Software Developer

Den Haag, Netherlands
Toptal Member Since
June 27, 2019

Kai has over ten years of experience in programming from embedded systems engineering for motor engines to scalable web architectures handling TB of data. He is passionate about challenging problems that require researching in-depth math or complicated algorithms to create reliable solutions that create a wow factor for clients and users.


Three.js, Pandas, NumPy, Django, Express.js, GraphQL, React, TypeScript
VanBerlo B.V.
Unity, Bluetooth Low Energy (LE), TensorFlow, React, Express.js, NumPy, ESP32...
Robert Bosch GmbH
Python, JavaScript, C#, .NET, Perl, C++, C




Preferred Environment

Zsh, Shell, Python, TypeScript, React, Visual Studio Code (VS Code)

The most amazing...

...application I've built was a smart golf ball with automated signal processing, advanced physics, test bench, and iOS Watch App and Lightning connectivity.

Work Experience

Co-founder, Full-stack Developer

2016 - PRESENT
  • Collaborated with a Taiwanese Bluetooth beacon producer to develop an indoor localization and tracking solution for industrial IoT applications.
  • Designed and developed the project management web application with embedded video conferencing via WebRTC for a German consultancy.
  • Designed and developed a client portal for a law firm to manage cases, and reuse previously created case templates.
  • Developed an HTML5 UI for a pick-and-place application for a robot. The UI communicates with ROS to monitor and set different parameters of the system. It also has a 3D viewer to visualize point-clouds from a depth-camera, and allows users to set ROI and other parameters within the 3D viewer (Three.js).
  • Designed and developed an ERP system for a French resource trader, that allows forecast management, HR tooling, CRM tooling, and basic knowledge management.
  • Developed a trading simulation game in cooperation with the TU Delft for their serious gaming program track.
Technologies: Three.js, Pandas, NumPy, Django, Express.js, GraphQL, React, TypeScript

Full-stack Developer

2015 - 2018
VanBerlo B.V.
  • Digitized analog water meters, with an embedded camera system that transferred and automatically extracted the readings to Cloud storage.
  • Developed a modular prototyping system for a car demonstrator to interact, orchestrate, and debug multiple hardware and sensor nodes (computers, tablets, phones, and embedded systems with Wi-Fi).
  • Developed an AR mobile app to make a book more interactive.
  • Created a prototype from an embedded 9DoF sensor that publishes the data via BLE to a mobile phone game developed in Unity.
  • Designed and developed middleware on a boat system to separate a hardware supplier and UI, allowing other parties to develop applications and modules on top of that API.
  • Developed an app and toolchain around a smart golf ball solution to record and process radar signals, which are then transferred to a Cloud application to perform pattern matching, and to determine the speed, distance, and rotational speed of the golf ball.
Technologies: Unity, Bluetooth Low Energy (LE), TensorFlow, React, Express.js, NumPy, ESP32, Arduino

Software System Developer

2010 - 2015
Robert Bosch GmbH
  • Analyzed and implemented customer requests, and focused on the low-level functions of the motor engine.
  • The process included: DevOps (Custom tool developments for build process), custom tool development for resource analysis, knowledge management using Wiki, networking and CAN communication, and immobilizer and anti-tampering protection.
Technologies: Python, JavaScript, C#, .NET, Perl, C++, C

Pick-it N.V.

Rebuilt the HTML front end in TypeScript and React. Designed and developed the front-end architecture to handle complex states and interactions with the Robot Operating System (ROS). Added support for the modern JavaScript ES6 syntax like async, await, and decorators.


Application for legal client management developed in cooperation with a Dutch law firm.

Project Management Tool for German Consultancy

This is a tool that allows the support of the consultancy process with multiple clients. It includes features such as file upload, event planning, to do lists, and conferencing.
2012 - 2015

Master of Science Degree in Management of Technology - Specialization in ICT

Delft University of Technology - Delft, Netherlands

2007 - 2010

Bachelor of Engineering Degree in Computer Engineering

Baden-Wuerttemberg Cooperative State University (DHBW) - Stuttgart, Germany


React, MobX, REST APIs, Graphene-Django, Python Asyncio, NumPy, Pandas, Node.js, Three.js, TensorFlow, WebRTC, Office API


MQTT, Webpack, Figma, Shell, Zsh, GitHub, Jenkins, Sketch, Prisma


Django, Django REST Framework, Next.js, .NET, Express.js, Unity


Visual Studio Code (VS Code), Amazon EC2, Firebase, Arduino, Bluetooth Low Energy (LE), Heroku, Adobe Suite, Kubernetes


TypeScript, JavaScript, Python, C, ECMAScript (ES6), C++, Perl, CoffeeScript, GraphQL, PHP, C#


PostgreSQL, Elasticsearch, Hasura, Google Cloud, MySQL, MongoDB


DevOps, Agile, Scrum


Back-end Development, Linux Servers, Microsoft 365, ESP32, Linux Device Driver, WebSockets, Framer Prototyping, Robot Operating System (ROS), V-Model

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