Beschreibung

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.

Branchenexpertise

Sprachen

Deutsch
Muttersprachlich oder zweisprachig
Englisch
Verhandlungssicher
Japanisch
Verhandlungssicher

Arbeitsortpräferenzen

Nur remote

Führt Projekte hauptsächlich remote aus

IT services, software products
Senior .NET / iOS / MAUI Architect · In-House Products & Client Projects
DIGITALAGENTUREN & IT-CONSULTING
Oktober 2023 - Heute (2 Jahre und 8 Monate)
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
MEDIZIN
November 2025 - Heute (7 Monate)
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
LUFT- & RAUMFAHRT
Juni 2022 - Januar 2023 (7 Monate)
Düsseldorf, Deutschland
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