Description

I build security-critical software for clients who can't afford to get it wrong.

My focus is applied cryptography, mobile device management, and cross-platform development with .NET MAUI. I'm the author of the SaQura Cryptographic Suite — a high-security library for .NET 8+ (AES-256, RSA-4096, ECC, Post-Quantum, Argon2), published on NuGet. I run my own iOS apps in the App Store (Sc4nR, Loki Radar) and have shipped production software for German public sector, university hospitals, forensic medicine, and aviation startups.

20+ years of professional software engineering. Senior-level architecture, hands-on implementation. Core stacks: C# / .NET 8+ / .NET MAUI, Swift / SwiftUI, TypeScript / Node.js / React / Next.js, PostgreSQL, Docker / Kubernetes, AWS / Azure / GCP. Compliance experience: GDPR, APPI (Japan), HIPAA.

I work fully remote from Kyoto, Japan, with a reliable daily overlap of 09:00–12:00 CET (= 17:00–20:00 JST) for European clients. All client communication in English or German. Billing is straightforward B2B — reverse-charge for EU clients, payment to an EU bank account, no chasing across timezones.

Available now for engagements ranging from quick architecture reviews to multi-month implementation work. Happy to discuss your project — feel free to reach out.

Industry field of expertise

Languages

German
Native or bilingual
English
Fluent
Japanese
Fluent

Workplace preferences

Remote only

Primarily works remotely

IT services, software products
Senior .NET / iOS / MAUI Architect · In-House Products & Client Projects
DIGITAL AND IT
October 2023 - Today (2 years and 8 months)
Kyoto, Japan
Security-critical software development for DACH (Germany/Austria/Switzerland) and international clients, plus development of an in-house product portfolio around cryptography, MDM, and cross-platform engineering.
In-house products:
SaQura Cryptographic Suite — High-security library for .NET 8+ (AES-256, RSA-4096, ECC,
Post-Quantum, Argon2). Published on NuGet.
KyotoTech Logger — Central log management for .NET 8+; native Swift port for iOS, macOS,
tvOS, watchOS.
KyotoTech PN — Push-notification service for iOS (APNS) and Android (FCM), MIT-licensed.
KyotoTech Map Server — Self-hosted OpenStreetMap infrastructure with Vector Tiles,
Valhalla routing, geocoding.
Sc4nR — iOS privacy-first scanner (QR, barcode, NFC, OCR, offline). On the App Store.
Loki Radar — iOS app for managing private locations. On the App Store.
KisoStats — macOS menu-bar system monitor.
In parallel, multiple active client projects in the DACH region (logistics, enterprise IT, healthcare) and IT consulting in Japan in the healthcare sector.

Tech stack: C#, .NET 8+, .NET MAUI, ASP.NET Core, Blazor, SignalR, Entity Framework Core, Dapper, Swift, SwiftUI, Objective-C, TypeScript, Node.js, Fastify, Drizzle ORM, React, Next.js, Astro, Vite, Tailwind CSS, PostgreSQL, PostGIS, SQL Server, Redis, Neo4j, Docker, Kubernetes, AWS, Azure, GCP, MinIO, OpenStreetMap, Valhalla, MapLibre, AES-256, RSA-4096, PostQuantum, JWT, FIDO2, Argon2, APNS, FCM, Firebase Admin, Stripe.
C# .NET Blazor .Net Maui SQL
HÄLSA Dental Clinic
Full-Stack Website, Hosting & IT Operations
MEDICAL
November 2025 - Today (7 months)
Kyoto, Japan
End-to-end delivery and ongoing operation of the online presence of a modern dental clinic. Full responsibility for website, server, domain, and technical infrastructure.
Concept, design, and development of a bilingual website (Japanese / English)
Service catalogue, pricing information, team profiles, gallery, contact & directions
Online appointment booking with integration of multiple contact channels (phone, web form,
LINE, Instagram)
Patient education blog
Responsive, performance-optimized layout
Hosting on own server infrastructure; domain / DNS management; TLS/HTTPS; backups
Ongoing service operation since launch (maintenance, updates, monitoring)
Tech stack: HTML5, CSS3, JavaScript, web CMS, Linux server hosting, Nginx, TLS/HTTPS, domain / DNS management, responsive design, multilingual (JP/EN), online appointment booking, LINE integration, Instagram integration
HTML5 CSS3 JavaScript C# API REST
Aviation / Ground Operations · Germany
Senior Mobile Developer
AVIATION AND AEROSPACE
June 2022 - January 2023 (7 months)
Düsseldorf, Germany
Design and development of a cross-platform mobile app (iOS & Android) for a startup operating in the environment of a major German airport. Used in operational airport contexts in ground operations / aero services.
Workshop phase for requirements gathering and architecture decisions
Cross-platform implementation with shared code for iOS and Android
Continuous further development across multiple iterations
Mobile backend integration, offline capability, auth flows
UI/UX implementation and store deployment

Tech stack: C#, .NET MAUI / Xamarin.Forms, iOS, Android, REST APIs, mobile UX, offline-first.
C# .Net Maui Xamarin iOS Android