Hans – Flutter, Dart, Firebase

A platform that makes welding inspection fully digital for construction and infrastructure projects (buildings, metro lines, amusement rides). Before it, there was no fully digital way to run inspections, analyze the results and deliver a certified report. He joined after the proof of concept, set the architecture direction, worked directly with industry experts to turn their needs into technical tasks, and built key features: interactive 3D views of welds, image annotation tools and offline-first error reporting.

• Set the architecture direction for a scalable codebase after the proof-of-concept stage
• Turned input from welding inspection experts into concrete technical requirements and tasks
• Built a custom depth-map shader library for interactive 3D views of welding joints
• Built a set of custom Flutter packages for annotating inspection images
• Designed and shipped an offline-first logging and error-reporting system that gave the team performance insights for product decisions

A B2B expense management and receipt-tracking platform with tens of thousands of daily users. A full rewrite of its 10-year-old Angular app had failed in the hands of a single junior developer with no support. He was brought in to rescue the project, finished the Flutter rewrite on time so the company met its contract obligations, and built a custom caching system with optimistic UI that cut loading times from 30+ seconds to under 1 second.

• Took over and rescued a failed Angular-to-Flutter rewrite, delivering it on time
• Cut loading times from 30+ seconds to under 1 second by building a custom caching system with optimistic UI updates
• Integrated Firebase and a JSON:API backend

An installer app for a company that designs, installs and manages home heat pumps. Field installers needed one tool to coordinate work before, during and after installation. He built an app that gives them the full history of each site, info on other teams working there, and on-site troubleshooting, diagnostics and commissioning of devices over Bluetooth, Wi-Fi or cellular.

• Built the installer app covering the full installation cycle, from pre-install to commissioning
• Added device troubleshooting, diagnostics and commissioning over Bluetooth, Wi-Fi and cellular
• Split the installer and consumer apps into separate codebases, which made the dev team more productive
• Built a custom Dart tool that automatically regenerates packages when the gRPC backend changes
• Simplified job workflows for field installers
• Handed the project over to the internal team, with documentation

A platform that connects football coaches with players remotely through live video, chat and async feedback. The client already had the player app but no way to manage coaches, players and sessions. He designed and built the foundation of a Flutter Web admin platform for that, then handed it over with documentation to another team to finish.

• Designed a modular Flutter Web architecture that lets coaches manage live training sessions
• Built the core admin features for managing coaches, players and sessions
• Wrote the architecture docs and handed the project to a junior team

A consumer app for a company that makes, installs and manages whole-home batteries, letting owners monitor and control their battery. As the only front-end developer, he designed, built and maintained the iOS and Android app from scratch, then handed it over to new maintainers with full documentation.

• Built the battery companion app from scratch as the only front-end developer, with a scalable, feature-based architecture
• Worked with the backend team on the GraphQL API design
• Turned Figma designs into a responsive, localized UI
• Delivered fully documented iOS and Android apps to the new maintainers

An inventory app for stores that sell scratch-off lottery tickets, where every ticket sold has to be tracked individually. The app runs on handheld barcode scanners so clerks can scan and count tickets quickly. He wrote native Android (Kotlin) code to talk to the scanner hardware and connected it to the Flutter app.

• Integrated built-in barcode scanner hardware into the Flutter app through native Android (Kotlin) code
• Built a Flutter–native bridge for fast ticket scanning and inventory counts

A proof-of-concept app for a smart insole that measures balance, step force and other metrics. He built an app that pairs with the insoles over a custom Bluetooth LE protocol, decodes the raw sensor data and shows it as a real-time animated visualization.

• Built a Flutter proof of concept that pairs with custom BLE hardware
• Decoded the raw BLE sensor data stream from a custom protocol
• Built real-time animated visualizations of balance and step-force data

A new stock trading platform built from the ground up. As the founding front-end developer, he designed and built the mobile app from scratch to launch on iOS and Android, hired and mentored a small team, and set up the architecture, testing practices and security approach for sensitive personal data.

• Led the iOS and Android apps from first concept to launch as the founding front-end developer
• Hired, led and mentored two developers, including in TDD
• Put in place security measures to protect sensitive user data across the whole app
• Set up the architecture, testing strategy and docs so the team could work on its own

A brain-training app with exercises built around rich animations. He moved the app from Flutter 1 to Flutter 2, rebuilt key legacy parts with BLoC, built many of the exercise animations, and trained the company’s in-house developer who took over the app.

• Moved the codebase from Flutter 1 to Flutter 2
• Rebuilt key legacy parts with BLoC to make the app easier to scale and maintain
• Built custom widgets and complex animations for the exercises
• Trained the in-house developer who took over the app

A white-label restaurant ordering system with kiosk and web versions and a built-in rewards program. He helped design an architecture where a single config file sets each client’s branding, so one codebase serves many restaurant brands.

• Helped design and build a white-label ordering system with a customer rewards program
• Set up config-based branding so one codebase ships to many restaurant clients
• Delivered both web and kiosk versions from one Flutter codebase

A sports coaching platform for kids. Players follow video “skill paths”, upload videos of themselves doing each skill and challenge each other head-to-head. He rewrote the outdated native iOS and Android apps as a single Flutter app on top of the existing API.

• Rewrote the native iOS and Android apps as one Flutter codebase
• Built video skill paths, video uploads and head-to-head challenges on the existing API