Christian Horder
Software Architect & 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
As an experienced Software Architect with over 25 years of professional experience – self-employed since 1998 – I support companies in designing and implementing tailor-made software solutions. My focus is on transforming legacy systems into future-proof architectures and developing scalable enterprise applications.
I accompany the entire software lifecycle - from requirements analysis through architecture design to implementation and deployment. I rely on modern technologies such as cloud-native architectures, containerization, and AI-assisted development. My goal is to develop maintainable, testable, and scalable software that creates long-term value.
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
- Dipl.-Informatiker (FH)Hochschule Karlsruhe
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
- 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. 12 software products, 6 of them 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.