Senior Software Developer with more than 10 experience creating software solutions for complex business needs
Aktualisiert am 27.03.2026
Profil
Freiberufler / Selbstständiger
Remote-Arbeit
Verfügbar ab: 05.03.2026
Verfügbar zu: 100%
davon vor Ort: 40%
Backend Development
Fullstack Development
Software Architecture
C#
.NET
SQL
Angular
React
Ruby on Rails
React Native
Softwarearchitektur
Teamleading
Azure
Flutter
German
Muttersprache
English
C2

Einsatzorte

Einsatzorte

Mainz (+50km)
Deutschland, Schweiz, Österreich
möglich

Projekte

Projekte

1 year 1 month
2025-01 - 2026-01

Extension of existing functionality

Full-Stack Developer & Data Engineer C# .NET .NET Framework ...
Full-Stack Developer & Data Engineer

Maintenance and extension of a large, modular software suite for sports event management

  • Extension of existing functionality
  • Optimization of database queries and development of an AI-compatible data aggregation strategy
  • Moderniza on of legacy components 
C# .NET .NET Framework ASP.NET VB.NET WPF Entity Framework SQL-Server REST-APIs Github Angular jQuery Stored Procedures Azure Identity Management Azure DevOps OpenAPI / Swagger Legacy Modernization
UEFA / Sports & Event Management
1 year 1 month
2025-01 - 2026-01

Successful rollout of the billing component

Software Engineering C# .NET Entity Framework ...
Software Engineering

Development of a state-of-the-art billing platform with integrated quote and invoice generation for a complex greenfield project in cinema advertising

  • Successful rollout of the billing component for a company-wide greenfield project
  • Complex billing processes including invoice generation and posting for clients and cinema operators 
C# .NET Entity Framework Aspire Docker Blazor Angular TypeScript Azure REST-APIs Clean Architecture CRM Diamant Accounting XUnit Auth0 Scalar CI/CD Modular Monolith
Weischer Media / Media, Billing
1 year
2025-01 - 2025-12

Full-Stack Development & Consulting

C# .NET Entity Framework ...

Design and development of a large-scale employee management and payroll system serving hundreds of public sector clients 

  • Consulting, design and development of various components in cross-organizational Scrum@Scale teams 
  • Integration of components across multiple programming languages and toolchains 

C# .NET Entity Framework Vue Java Maven Kubernetes KeyCloak SOAP REST-APIs Microservices Cobol Monolith Codebase Workflow Engine Camunda Scrum@Scale
AKDB / Public Sector, Billing, CRM
1 year
2025-01 - 2025-12

Building interfaces for media capture and conversion

Software Developer C# .NET ASP.NET Core ...
Software Developer

Development of an internal media transfer system for digitization and streamlining of media assets

  • Building interfaces for media capture and conversion
  • Integration with existing editorial and archival systems 

C# .NET ASP.NET Core Entity Framework SQL Server REST-APIs Azure Docker FFmpeg Media Formats FTP/SFTP File Synchronization OpenAPI / Swagger
Deutsche Welle / Media, TV, Broadcasting
1 year
2024-01 - 2024-12

Development of a cross-platform iOS and Android mobile application

Software Developer React Native iOS Android ...
Software Developer
  • Development of a cross-platform iOS and Android mobile application for warehouse management with AI-powered features. 
React Native iOS Android Mobile TypeScript REST-APIs ChatGPT OpenAI LLM-Integration JSON NoSQL
Logistics
1 year 8 months
2023-05 - 2024-12

Software suite for maritime insurance solutions

Development Lead, Software Architect, Backend Developer C# .NET ASP.NET Core ...
Development Lead, Software Architect, Backend Developer
  • Designing the software architecture for a modern web-based solution to replace a decade-old legacy system
  • Leading, coaching and reviewing the international development team
  • Backend implementation of highly complex business logic
  • Development of an invoicing and accounting verification system
  • Onboarding of the offshore maintenance team
C# .NET ASP.NET Core Entity Framework SQL-Server Azure Github GitHub Actions Angular DevExpress ag Grid REST-APIs Clean Architecture DDD Azure Identity Management Docker Terraform CI/CD NUnit Cypress OpenAPI / Swagger
Lufthansa Industry Solutions / Insurance, Maritime
9 years 1 month
2015-01 - 2024-01

Ongoing development of the web application

Full-Stack Developer & Development Lead Ruby on Rails Postgres React ...
Full-Stack Developer & Development Lead

Development, maintenance and opmiza on of a complex custom B2B platform for wholesale. 

  • Ongoing development of the web application including several major migrations and version upgrades 
  • International market rollout 
  • Development Lead from 2018 

Ruby on Rails Postgres React Bootstrap JavaScript TypeScript Microservices REST-APIs Synchronization Engine ERP / ERP System SAP Integration CI/CD
E-Commerce / Maier Sports GmbH
9 months
2022-09 - 2023-05

Establishing a new software architecture

Development Lead, Full-Stack Developer C# .NET ASP.NET Core ...
Development Lead, Full-Stack Developer

Greenfield development of a web-based chartering and brokerage system for the maritime industry 

  • Establishing a new software architecture 
  • Implementation of backend and frontend features 
  • Coordinating development tasks across the team 
  • Automated test infrastructure 
  • Complex integrations with internal and external data sources 
  • API development for other projects 
  • Onboarding of the offshore maintenance team 
  • Successful migration to the new system with significant productivity gains in the department 

C# .NET ASP.NET Core Entity Framework SQL-Server Azure Github GitHub Actions Angular ag Grid REST-APIs Clean Architecture Azure Identity Management Docker Terraform Quartz CI/CD NUnit Cypress Large-Scale Data Processing OpenAPI / Swagger
Lufthansa Industry Solutions / Maritime, Chartering, Brokerage
1 year 1 month
2022-01 - 2023-01

Development and maintenance of an application

Software Developer / Maintainer Ruby on Rails Postgres React ...
Software Developer / Maintainer
  • Development and maintenance of an application for a Swiss non-profit organization. Custom CMS for managing blog posts and other media-based content. 
Ruby on Rails Postgres React JavaScript REST-APIs CMS Media ImageMagick HTML/CSS Newsletter Mailing
Neustarter / Social Impact, Press, Social Media
9 months
2022-01 - 2022-09

New multi-tenant web application

Full-Stack Developer C# ASP.NET Core Entity Framework ...
Full-Stack Developer

Greenfield development of a web-based system for managing operational tasks on private sea voyages 

  • New multi-tenant web application 
  • Compliance-compliant processes for logging and conducting safety measures on sea voyages 
  • Crew management and document management 
  • Distributed systems with message-based synchronization engine for centralized data management 
  • Successful rollout for top international clients 

C# ASP.NET Core Entity Framework RavenDB (NoSQL) Flutter Dart REST-APIs Message Queue Data Synchronization NLog NUnit Azure Multi-Tenancy Document Management Systems OpenAPI / Swagger
Lufthansa Industry Solutions / Maritime, Compliance

Aus- und Weiterbildung

Aus- und Weiterbildung

3 years 6 months
2015-04 - 2018-09

Study - Computer Science

BSc., Ludwig-Maximilians-Universität München
BSc.
Ludwig-Maximilians-Universität München
Bachelor Thesis: on request

Position

Position

  • Senior Software Developer
  • Software Architect
  • Development Lead

Kompetenzen

Kompetenzen

Top-Skills

Backend Development Fullstack Development Software Architecture C# .NET SQL Angular React Ruby on Rails React Native Softwarearchitektur Teamleading Azure Flutter

Produkte / Standards / Erfahrungen / Methoden

Profile

Freelance Senior Software Developer and Architect with over 10 years of experience in the .NET and C# ecosystem. Specialized in software architecture, greenfield development and legacy modernization for enterprise clients such as Lufthansa, UEFA and TÜV SÜD. Takes on technical leadership, team management and hands-on development from backend to frontend.


Skills and Expertise

Backend

  • C#, .NET, ASP.NET Core, Entity Framework
  • Microservices, Clean Architecture, CQRS
  • SQL Server, PostgreSQL, Redis, RavenDB (NoSQL)
  • REST-APIs, gRPC, Message Queues 


Frontend/ Mobile

  • Angular, React, React Native, Flutter
  • HTML / CSS / JavaScript / TypeScript
  • Blazor, WPF, Java 


Cloud, DevOps & Testing

  • Azure, AWS, Docker, Terraform
  • Azure DevOps, GitHub Actions, CI/CD
  • Identity Management (AD, Auth0, KeyCloak)
  • NUnit, XUnit, Cypress 


AI & Methodology

  • LLM-Integration (OpenAI API, Claude API)
  • RAG, Prompt Engineering, Custom Models 


Leadership & Processes

  • Software Architecture
  • Technical Leadership, Mentoring
  • SCRUM / Agile, DDD / BDD / TDD
  • Code Reviews, Sonar, Lint
  • Jira, Confluence, Backlog Management


Tools

Visual Studio, Rider, VS Code, Git


Professional Experience

03/2018 - today

Role: Freelance Software Developer


Tasks:

  • Architecture and greenfield development of complex .NET applica ons as well as moderniza on of legacy systems for clients such as TÜV SÜD, Lu hansa, UEFA and Deutsche Welle.
  • Technical leadership in distributed teams, including onboarding and mentoring of developers
  • End-to-end delivery from requirements analysis through architecture to produc on deployment 


12/2013 ? 02/2018

Role: Web Developer

Customer: Zoom7 GmbH 


Tasks:

    • Design and implementation of web applications as well as backends for mobile apps, social networks and e-commerce platforms 

    Branchen

    Branchen

    • Maritime
    • Industrial
    • Insurance
    • Brokerage

    Einsatzorte

    Einsatzorte

    Mainz (+50km)
    Deutschland, Schweiz, Österreich
    möglich

    Projekte

    Projekte

    1 year 1 month
    2025-01 - 2026-01

    Extension of existing functionality

    Full-Stack Developer & Data Engineer C# .NET .NET Framework ...
    Full-Stack Developer & Data Engineer

    Maintenance and extension of a large, modular software suite for sports event management

    • Extension of existing functionality
    • Optimization of database queries and development of an AI-compatible data aggregation strategy
    • Moderniza on of legacy components 
    C# .NET .NET Framework ASP.NET VB.NET WPF Entity Framework SQL-Server REST-APIs Github Angular jQuery Stored Procedures Azure Identity Management Azure DevOps OpenAPI / Swagger Legacy Modernization
    UEFA / Sports & Event Management
    1 year 1 month
    2025-01 - 2026-01

    Successful rollout of the billing component

    Software Engineering C# .NET Entity Framework ...
    Software Engineering

    Development of a state-of-the-art billing platform with integrated quote and invoice generation for a complex greenfield project in cinema advertising

    • Successful rollout of the billing component for a company-wide greenfield project
    • Complex billing processes including invoice generation and posting for clients and cinema operators 
    C# .NET Entity Framework Aspire Docker Blazor Angular TypeScript Azure REST-APIs Clean Architecture CRM Diamant Accounting XUnit Auth0 Scalar CI/CD Modular Monolith
    Weischer Media / Media, Billing
    1 year
    2025-01 - 2025-12

    Full-Stack Development & Consulting

    C# .NET Entity Framework ...

    Design and development of a large-scale employee management and payroll system serving hundreds of public sector clients 

    • Consulting, design and development of various components in cross-organizational Scrum@Scale teams 
    • Integration of components across multiple programming languages and toolchains 

    C# .NET Entity Framework Vue Java Maven Kubernetes KeyCloak SOAP REST-APIs Microservices Cobol Monolith Codebase Workflow Engine Camunda Scrum@Scale
    AKDB / Public Sector, Billing, CRM
    1 year
    2025-01 - 2025-12

    Building interfaces for media capture and conversion

    Software Developer C# .NET ASP.NET Core ...
    Software Developer

    Development of an internal media transfer system for digitization and streamlining of media assets

    • Building interfaces for media capture and conversion
    • Integration with existing editorial and archival systems 

    C# .NET ASP.NET Core Entity Framework SQL Server REST-APIs Azure Docker FFmpeg Media Formats FTP/SFTP File Synchronization OpenAPI / Swagger
    Deutsche Welle / Media, TV, Broadcasting
    1 year
    2024-01 - 2024-12

    Development of a cross-platform iOS and Android mobile application

    Software Developer React Native iOS Android ...
    Software Developer
    • Development of a cross-platform iOS and Android mobile application for warehouse management with AI-powered features. 
    React Native iOS Android Mobile TypeScript REST-APIs ChatGPT OpenAI LLM-Integration JSON NoSQL
    Logistics
    1 year 8 months
    2023-05 - 2024-12

    Software suite for maritime insurance solutions

    Development Lead, Software Architect, Backend Developer C# .NET ASP.NET Core ...
    Development Lead, Software Architect, Backend Developer
    • Designing the software architecture for a modern web-based solution to replace a decade-old legacy system
    • Leading, coaching and reviewing the international development team
    • Backend implementation of highly complex business logic
    • Development of an invoicing and accounting verification system
    • Onboarding of the offshore maintenance team
    C# .NET ASP.NET Core Entity Framework SQL-Server Azure Github GitHub Actions Angular DevExpress ag Grid REST-APIs Clean Architecture DDD Azure Identity Management Docker Terraform CI/CD NUnit Cypress OpenAPI / Swagger
    Lufthansa Industry Solutions / Insurance, Maritime
    9 years 1 month
    2015-01 - 2024-01

    Ongoing development of the web application

    Full-Stack Developer & Development Lead Ruby on Rails Postgres React ...
    Full-Stack Developer & Development Lead

    Development, maintenance and opmiza on of a complex custom B2B platform for wholesale. 

    • Ongoing development of the web application including several major migrations and version upgrades 
    • International market rollout 
    • Development Lead from 2018 

    Ruby on Rails Postgres React Bootstrap JavaScript TypeScript Microservices REST-APIs Synchronization Engine ERP / ERP System SAP Integration CI/CD
    E-Commerce / Maier Sports GmbH
    9 months
    2022-09 - 2023-05

    Establishing a new software architecture

    Development Lead, Full-Stack Developer C# .NET ASP.NET Core ...
    Development Lead, Full-Stack Developer

    Greenfield development of a web-based chartering and brokerage system for the maritime industry 

    • Establishing a new software architecture 
    • Implementation of backend and frontend features 
    • Coordinating development tasks across the team 
    • Automated test infrastructure 
    • Complex integrations with internal and external data sources 
    • API development for other projects 
    • Onboarding of the offshore maintenance team 
    • Successful migration to the new system with significant productivity gains in the department 

    C# .NET ASP.NET Core Entity Framework SQL-Server Azure Github GitHub Actions Angular ag Grid REST-APIs Clean Architecture Azure Identity Management Docker Terraform Quartz CI/CD NUnit Cypress Large-Scale Data Processing OpenAPI / Swagger
    Lufthansa Industry Solutions / Maritime, Chartering, Brokerage
    1 year 1 month
    2022-01 - 2023-01

    Development and maintenance of an application

    Software Developer / Maintainer Ruby on Rails Postgres React ...
    Software Developer / Maintainer
    • Development and maintenance of an application for a Swiss non-profit organization. Custom CMS for managing blog posts and other media-based content. 
    Ruby on Rails Postgres React JavaScript REST-APIs CMS Media ImageMagick HTML/CSS Newsletter Mailing
    Neustarter / Social Impact, Press, Social Media
    9 months
    2022-01 - 2022-09

    New multi-tenant web application

    Full-Stack Developer C# ASP.NET Core Entity Framework ...
    Full-Stack Developer

    Greenfield development of a web-based system for managing operational tasks on private sea voyages 

    • New multi-tenant web application 
    • Compliance-compliant processes for logging and conducting safety measures on sea voyages 
    • Crew management and document management 
    • Distributed systems with message-based synchronization engine for centralized data management 
    • Successful rollout for top international clients 

    C# ASP.NET Core Entity Framework RavenDB (NoSQL) Flutter Dart REST-APIs Message Queue Data Synchronization NLog NUnit Azure Multi-Tenancy Document Management Systems OpenAPI / Swagger
    Lufthansa Industry Solutions / Maritime, Compliance

    Aus- und Weiterbildung

    Aus- und Weiterbildung

    3 years 6 months
    2015-04 - 2018-09

    Study - Computer Science

    BSc., Ludwig-Maximilians-Universität München
    BSc.
    Ludwig-Maximilians-Universität München
    Bachelor Thesis: on request

    Position

    Position

    • Senior Software Developer
    • Software Architect
    • Development Lead

    Kompetenzen

    Kompetenzen

    Top-Skills

    Backend Development Fullstack Development Software Architecture C# .NET SQL Angular React Ruby on Rails React Native Softwarearchitektur Teamleading Azure Flutter

    Produkte / Standards / Erfahrungen / Methoden

    Profile

    Freelance Senior Software Developer and Architect with over 10 years of experience in the .NET and C# ecosystem. Specialized in software architecture, greenfield development and legacy modernization for enterprise clients such as Lufthansa, UEFA and TÜV SÜD. Takes on technical leadership, team management and hands-on development from backend to frontend.


    Skills and Expertise

    Backend

    • C#, .NET, ASP.NET Core, Entity Framework
    • Microservices, Clean Architecture, CQRS
    • SQL Server, PostgreSQL, Redis, RavenDB (NoSQL)
    • REST-APIs, gRPC, Message Queues 


    Frontend/ Mobile

    • Angular, React, React Native, Flutter
    • HTML / CSS / JavaScript / TypeScript
    • Blazor, WPF, Java 


    Cloud, DevOps & Testing

    • Azure, AWS, Docker, Terraform
    • Azure DevOps, GitHub Actions, CI/CD
    • Identity Management (AD, Auth0, KeyCloak)
    • NUnit, XUnit, Cypress 


    AI & Methodology

    • LLM-Integration (OpenAI API, Claude API)
    • RAG, Prompt Engineering, Custom Models 


    Leadership & Processes

    • Software Architecture
    • Technical Leadership, Mentoring
    • SCRUM / Agile, DDD / BDD / TDD
    • Code Reviews, Sonar, Lint
    • Jira, Confluence, Backlog Management


    Tools

    Visual Studio, Rider, VS Code, Git


    Professional Experience

    03/2018 - today

    Role: Freelance Software Developer


    Tasks:

    • Architecture and greenfield development of complex .NET applica ons as well as moderniza on of legacy systems for clients such as TÜV SÜD, Lu hansa, UEFA and Deutsche Welle.
    • Technical leadership in distributed teams, including onboarding and mentoring of developers
    • End-to-end delivery from requirements analysis through architecture to produc on deployment 


    12/2013 ? 02/2018

    Role: Web Developer

    Customer: Zoom7 GmbH 


    Tasks:

      • Design and implementation of web applications as well as backends for mobile apps, social networks and e-commerce platforms 

      Branchen

      Branchen

      • Maritime
      • Industrial
      • Insurance
      • Brokerage

      Vertrauen Sie auf Randstad

      Im Bereich Freelancing
      Im Bereich Arbeitnehmerüberlassung / Personalvermittlung

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      Rufen Sie uns an +49 89 500316-300 oder schreiben Sie uns:

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