jrdevdesign

Hi, I am Johannes,

Developer

with

Business Focus

I build web and mobile products that solve real business problems. From discovery and MVPs to production rollout, I deliver secure, maintainable software with clear communication and fast iteration.

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Heat Pump Control

Expo

React Native

Android

Heat Pump Control is a mobile app for controlling and monitoring heat pumps, including setup, status insights, and device control workflows.

Voice Journal

Expo

React Native

Android

Voice Journal is a mobile app that allows you to record and transcribe your voice journal entries.

Body Composition Tracker

Expo

React Native

Android

Body Composition Tracker helps you measure body fat and lean mass from caliper readings, track progress over time, and keep all data local — available as a mobile app and web app.

TradingLog

Expo

React Native

Android

TradingLog is a mobile app that helps you to keep track of your trading and your progress.

PurePower

Expo

React Native

Android

PurePower is a mobile cycling app that connects to Bluetooth power meters and heart rate sensors to show live power, cadence, and GPS ride data, and to record and analyze your rides.

Bike Power Field

Monkey C

Connect IQ

Garmin

Bike Power Field is a Connect IQ data field for Garmin watches and Edge computers that displays live ANT+ bike power and cadence, especially useful on devices without native cycling power support.

Lifter

Expo

React Native

Android

Lifter is a mobile app that helps you to keep track of your workouts and your progress.

dChallenge

Solidity

Defichain

Next.js

dChallenge is a decentralized application that allows users to create and participate in challenges. You can bet that you will achive a certain goal and others have to confirm it for you to get your stake back.

Power Quote

Expo

React Native

Android

Power Quote is a mobile app to collect quotes from books, websites, and other apps and keep them visible on your Android home screen.

next market

Arweave

Ethereum

Solidity

next market is an NFT marketplace on which the files themselves are stored on the Arweave blockchain and are therefore immutable.

What

I do

Development

I design and build web and mobile applications with a practical MVP approach. You get short feedback cycles, transparent progress, and software that is secure, maintainable, and ready to scale.

Design Support

Design supports implementation, not the other way around. I focus on clear user flows, consistent interfaces, and documented decisions so teams can move faster with less project risk.