Hans Otto Wirtz
Software Engineer, CTO, Founder
AltVelo
2025
BubblyDoo
2018 - present
Spices.app
2022, 2025
3D Hanzi Generator
2021 - 2022
angular-react
2022 - 2023
React Done Tracker
2023
GraphQL Workers Subscriptions
2023
Zoemin Website
2018
s[MAS]h!
2017
BN Classic Website
2016 - 2017
Learning Chinese
2018 - present
LP50xx Breakout Board
2019
Wall-mounted computer
2018 - 2021
3D Printing
Treehouse
2011 - 2015
Lego Antwerp MOC
2023 - 2025
UAntwerp Snapchat Filters
2018
Ottomatisch
2016 - 2023
BubblyDoo Renderer
2018 - present
BubblyDoo Website
2018 - present
BubblyDoo Data Pipeline
2022 - present
Arbiter
Hi, I'm Hans Otto
I'm a software engineer from Antwerp, Belgium.
I have a passion for programming, solving complex problems, and learning new things.
I'm the co-founder and CTO of BubblyDoo, a company that creates personalized products for children.
AltVelo
2025
An alternative app for the Antwerp Velo.
🔧 iOS
🔧 Swift
🔧 SwiftUI
BubblyDoo
2018 - present
CTO and Co-Founder of BubblyDoo, an e-commerce startup creating personalized products for children.
🏷️ Entrepreneurship
Spices.app
2022, 2025
A creative project generating spice labels for your kitchen.
🔧 Next.js
🔨 3D printing
🔧 React
🏷️ Creative
3D Hanzi Generator
2021 - 2022
A tool for generating 3D models of Chinese characters.
🔨 3D printing
📚 Chinese
🏷️ Creative
🔧 Python
🔧 OpenSCAD
angular-react
2022 - 2023
A library for using Angular in React and React in Angular.
🔧 Angular
🔧 React
React Done Tracker
2023
A library that makes it easy to track the async state of a React tree.
🔧 React
GraphQL Workers Subscriptions
2023
A library/framework built on Cloudflare Workers providing distributed, topic-based GraphQL subscriptions.
🔧 GraphQL
🔧 Cloudflare Workers
🔧 WebSockets
Zoemin Website
2018
A website for Zoemin, a photographer (also my mom).
🔧 Ruby on Rails
🏷️ Client Project
s[MAS]h!
2017
An app for the MAS museum' Masked event.
🔧 Angular
🏷️ Client Project
🔧 WebSockets
BN Classic Website
2016 - 2017
A website for BN Classic, a yearly running event in Belgium.
🔧 Angular
🏷️ Client Project
Learning Chinese
2018 - present
Me learning Mandarin Chinese.
📚 Chinese
🏷️ Learning
LP50xx Breakout Board
2019
A breakout board for the LP50xx series of LED drivers.
🔧 Electronics
🧰 Autodesk Eagle
Wall-mounted computer
2018 - 2021
An art project in which I took a computer and mounted it on a board on the wall.
🏷️ Creative
🔧 Electronics
3D Printing
Me 3D printing stuff.
🔨 3D printing
Treehouse
2011 - 2015
A treehouse I modeled & built as a kid.
🏷️ Creative
🧰 Google SketchUp
🔨 Manual
Lego Antwerp MOC
2023 - 2025
A custom Lego model of the Antwerp skyline.
🏷️ Creative
UAntwerp Snapchat Filters
2018
Snapchat filters for the University of Antwerp.
🏷️ Creative
🧰 Adobe Illustrator
Ottomatisch
2016 - 2023
My one-person company for freelance work.
🏷️ Entrepreneurship
BubblyDoo Renderer
2018 - present
The in-house renderer for BubblyDoo.
🔧 React
🔧 WebGL
🔧 Cloudflare Workers
🔧 Vue.js
🔧 AWS Lambda
BubblyDoo Website
2018 - present
The website for BubblyDoo.
🔧 Next.js
🔧 React
🔧 Cloudflare Workers
🔧 AWS Lambda
BubblyDoo Data Pipeline
2022 - present
The data pipeline for BubblyDoo.
🔧 dbt
🧰 Fivetran
🧰 BigQuery
🧰 Looker Studio
Arbiter
A high frequency scraping tool and analyzer.
🔧 Node.js
🔧 PostgreSQL