Christian Horder
Software Architect & .NET Developer
Tailor-made software solutions and AI-powered custom solutions – for over 25 years, from requirements to a system running in production
Get in TouchAbout Me
Experienced Software Architect for sustainable enterprise solutions
I am a Software Architect and .NET developer from Landau in der Pfalz, Germany, and for more than 25 years I have designed and built software for very different industries – as an employee and, since 1998, also self-employed, from requirements to production. My focus is on service and integration architectures: gradually moving legacy applications to services and decoupling systems so that even central backends can be replaced later. CI/CD, security and automated tests are part of this, as are AI-assisted development with mandatory checks and the integration of LLMs into products.
At a Glance
- Software development and architecture for companies in Landau, Speyer, the Southern Palatinate and the Karlsruhe/Mannheim area on site, and remotely throughout Germany
- Service and integration architectures with .NET
- Modernization of legacy systems: from monolith to services
- AI-assisted software development with guardrails and LLM integration into products
- Technical project management and team leadership
- Industries: manufacturing, banking, energy, public transit, medical technology, e-commerce, hospitality, tourism
- M.Sc. Computer Science, IREB CPRE Foundation Level
- Deputy Chairman of JUST e.V. – Forum für Unternehmen, Landau
Strengths
- Analytical Thinking & Problem Solving
- Quality Awareness & Clean Code
- Team Leadership & Technical Lead
- Continuous Learning
- Technical Communication
Focus Areas
- Cloud-native Architectures
- Legacy Modernization
- API Design & Microservices
- DevOps & CI/CD
- AI Integration
Education
- M.Sc. Computer ScienceFernUniversität Hagen
- IREB CPRE Foundation LevelCertified Professional for Requirements Engineering
Languages
- GermanNative
- EnglishFull professional proficiency
Services
Tailor-made software solutions – from consulting to implementation
Architecture Consulting
Support with technical conception, system design and modernization strategy
- Analysis of existing architectures
- Cloud-native & microservice design
- Legacy modernization
- API design
- Technology consulting
Development & Coding
Reliable implementation from feature to release – also as an extended workbench for your team
- .NET/C# feature development
- Bugfixing
- REST APIs & Microservices
- Websites and web applications
- Third-party system integration
- CI/CD pipelines
AI Integration & Consulting
AI-powered custom solutions: consulting and implementation for integrating AI and large language models into existing systems
- LLM integration into existing applications
- RAG architectures & knowledge management
- Prompt engineering & AI workflows
- Feasibility analysis & prototyping
- Agentic AI & automation
Code Reviews
Review against quality standards, best practices and architecture principles with structured feedback
- Clean Code & SOLID
- Security & Performance
- Test coverage
- Architecture reviews
Skills
Technical expertise for modern software development
Backend & APIs
Frontend & Web
Cloud & DevOps
Architecture & Patterns
Databases
AI & Modern Tools
Testing & Quality
Methods & Tools
Industry Experience
Versatile expertise across different industry sectors
Projects
Freelance work and selected work from employment
Freelance Projects
Projects and products from my self-employment – self-employed since 1998.
Motorhome Rental Landau – Website Relaunch
- Replaces the previous website builder: 15 responsive pages with vehicles, prices, rental terms and FAQ
- Enquiries arrive with travel dates and preferred vehicle – form with invisible bot protection (Cloudflare Turnstile)
- Existing search results remain reachable: 301 redirects, structured data (JSON-LD) and sitemap
- Google services only after a click or consent; low-maintenance operation on Cloudflare Pages
House am Rhein / House Art – Event Landing Page
- Two house-music brands (House am Rhein & House Art) appear together – each with its own section on a single scrollable page, one shared deployment
- Dates, image galleries and a live countdown at a glance: high-performance vanilla frontend with scroll animations and responsive dark design
- Discoverable in search and correct previews when shared – via Open Graph, JSON-LD (Organization + Event), sitemap and image-optimized loading times
- Ticket sales integrated directly (ticket.io); operated on Docker/Nginx with SSL and a strict Content Security Policy
Online Art Shop
- A direct online sales channel for original artworks and commissioned paintings – with gallery, wishlist and shopping cart
- Different art formats can be maintained as variants and images are optimized automatically – built on a Clean Architecture backend with REST API
- Fast loading times and strong search visibility through a responsive Next.js frontend with Tailwind CSS
- Low-maintenance operation: Docker deployment with Nginx reverse proxy, SSL certificate and automated backups
Regional Rental Platform
- Neighbors rent out items and offer services – with booking system and calendar integration
- Offer descriptions are generated with AI support (OpenAI GPT); access is secured through JWT authentication with email verification
- Payouts to providers run automatically through the integrated payment connection
SmartHospital – Medical Letter Management
- Physician letters and discharge letters are created and managed FHIR-compliant – ready to connect to existing hospital systems
- Documents are produced as PDF/HTML from a template system, with access governed by roles (RBAC, JWT authentication)
- Built for long-term maintainability: Clean Architecture with CQRS pattern (MediatR), Repository pattern and 16 specialized projects
Nightclub & Hospitality Management
- Business software for nightclubs and hospitality businesses – modular in design and extensible by individual areas
- Evolved from a desktop solution (Visual Basic, Microsoft Access) into a web platform based on ASP.NET MVC
- Modules for communication (SMS, newsletter, social media), staff scheduling and booking system
- Operators maintain their own websites through a dedicated content management system, connected via REST API
- Native mobile apps for iOS and Android including per-venue branding
Selected Work from Employment
Selected projects from my permanent positions. They show my experience but are not client projects of my self-employment.
International automotive supplier 11/2017 – present
Software Architect / Technical Lead. Autonomous architecture, technology and standards decisions, aligned with the team manager. Architect and technical lead for the team's engineering software, partly under sole responsibility. Used in the development centres worldwide – from CAD design through bills of materials to change management.
Migration to a New PLM System
Technical lead, architect and developer
- All engineering applications move from SAP PLM to PTC Windchill – migration technically led: legacy systems analysed, their functions mapped to the new APIs, order of the switch agreed with the team manager
- New integration platform built in around 8 months: parts, CAD documents, BOMs with effectivity, change objects, health dashboard
- 5 dependent products switched to the new APIs with coordinated versions
AI-Assisted Software Development
Introduction and methodology
- Introduced Claude Code as a fixed part of delivery; mandatory context files in over 30 repositories
- Custom agent skills for CI, deployment, macro development and the integration API
- Mandatory checks before delivery: security review, automated tests, documentation checked against code
Jira & Tempo Timesheets Synchronization
Architect and developer
- Tempo resource plans are reconciled with Jira automatically – via an unattended background service
- Secure connection to the Atlassian platforms through REST API with token authentication
- Reliable continuous operation through robust error handling with logging and retry mechanisms
Rule-Based Mapping Engine
Architect and lead developer
- Classification data is turned into texts for drawings and BOMs via C# rules – a stateless service used by 4 platforms
- Compilations per call cut from approx. 63 to 0 and injection risk eliminated
- Safeguarded by 124 golden master tests
Identity & Access Management
Architect and lead developer
- Central authentication and authorization based on NIST RBAC, in production since 11/2020
- User data import redesigned: runtime reduced from approx. 3 h to approx. 8 min, around 5,900 missing users recovered
- Rebuilt in 2026 with server-side sessions, PBKDF2, login throttling and audit log; over 200 tests, all security review findings resolved; SSO with Entra ID prepared
Microservice Platform and Backend Abstraction
Architect and lead developer
- Monolithic desktop application gradually transformed into around 10 services: PLM data service, BOM service with web UI, drawing data for the CAD systems, employee directory, central access management
- An abstraction layer (2021) decoupled all services from the PLM backend and later made the system switch possible
- Shared contract packages, API versioning, health checks and correlation IDs; microservice target architecture and service dependency matrix (2024)
- Restructured to Clean Architecture (2024); annual upgrades from .NET Core 3 to .NET 9
CI/CD and Release Management
Lead developer and architect
- Introduced CI/CD, replacing the fully manual rollout of 10 components; now the standard for all products
- Staged release process Dev → Test → Prod with beta testers
- Central configuration service with failover at 9 sites
Earlier Employment
Financial Portal Platform
Technical project lead and team lead (5–7 developers)
- Leading a development team (5–7 members) implementing financial portals for national and international clients
- Development of secure transaction systems with high data protection and compliance requirements
- Integration of real-time market data and reporting functions for portfolio analysis
- Performance optimization for high user volumes and complex database queries
Production Planning System
Software Developer
- Design and implementation of an enterprise planning application with scalable multi-tier architecture based on WCF
- Development of backend services and frontend components for production planning
- Rollout management for intermediate versions to customer environment including deployment and testing
- Oracle database integration with optimized queries for large data volumes
Energy Trading Portal
Senior Software Developer and Consultant
- Design and development of portal solutions based on CMS, connected to the Endur energy trading system
- Requirements engineering and interface specification
Price Comparison and Shopping Portal
Senior Software Developer · IT service provider, partly on site at a major German internet service provider
- Responsible for the further development of a price comparison and shopping portal with country versions for Germany, Austria and the UK
- Architecture and further development of the core platform: product search and offer import
Telematics & Passenger Information
Product Owner and Project Manager
- Product ownership for telematics software
- Project management for national and international rollouts
Contact
Let's talk about your next project
Get in Touch
Do you have a project or challenge where I can support you? I look forward to hearing from you.