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I’m James Marshall, a Senior .NET contractor with over 12 years of experience delivering high-performance, production-critical software across desktop, mobile, and cross-platform environments. I specialise in real-time systems, distributed data synchronization, and scalable architecture, with recent work integrating AI-driven features into production applications. I thrive in autonomous or multidisciplinary teams, and I’m a strong advocate of clean architecture, test-driven development, and loosely coupled systems. I’ve delivered in defence, industrial, and commercial domains, and I’ve improved system reliability, reduced defects, and built maintainable solutions. I’m based in Devon, UK, hold active SC clearance, fluent in French, and hold a full UK driving license.…I’m James Marshall, a Senior .NET contractor with over 12 years of experience delivering high-performance, production-critical software across desktop, mobile, and cross-platform environments. I specialise in real-time systems, distributed data synchronization, and scalable architecture, with recent work integrating AI-driven features into production applications. I thrive in autonomous or multidisciplinary teams, and I’m a strong advocate of clean architecture, test-driven development, and loosely coupled systems. I’ve delivered in defence, industrial, and commercial domains, and I’ve improved system reliability, reduced defects, and built maintainable solutions. I’m based in Devon, UK, hold active SC clearance, fluent in French, and hold a full UK driving license.

James Marshall

PRO

Full Stack Developer, Web Developer, Programmer, +7

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I’m James Marshall, a Senior .NET contractor with over 12 years of experience delivering high-performance, production-critical software across desktop, mobile, and cross-platform environments. I specialise in real-time systems, distributed data synchronization, and scalable architecture, with recent work integrating AI-driven features into production applications. I thrive in autonomous or multidisciplinary teams, and I’m a strong advocate of clean architecture, test-driven development, and loosely coupled systems. I’ve delivered in defence, industrial, and commercial domains, and I’ve improved system reliability, reduced defects, and built maintainable solutions. I’m based in Devon, UK, hold active SC clearance, fluent in French, and hold a full UK driving license.…I’m James Marshall, a Senior .NET contractor with over 12 years of experience delivering high-performance, production-critical software across desktop, mobile, and cross-platform environments. I specialise in real-time systems, distributed data synchronization, and scalable architecture, with recent work integrating AI-driven features into production applications. I thrive in autonomous or multidisciplinary teams, and I’m a strong advocate of clean architecture, test-driven development, and loosely coupled systems. I’ve delivered in defence, industrial, and commercial domains, and I’ve improved system reliability, reduced defects, and built maintainable solutions. I’m based in Devon, UK, hold active SC clearance, fluent in French, and hold a full UK driving license.

Available to hire

United Kingdom

I’m James Marshall, a Senior .NET contractor with over 12 years of experience delivering high-performance, production-critical software across desktop, mobile, and cross-platform environments. I specialise in real-time systems, distributed data synchronization, and scalable architecture, with recent work integrating AI-driven features into production applications.

I thrive in autonomous or multidisciplinary teams, and I’m a strong advocate of clean architecture, test-driven development, and loosely coupled systems. I’ve delivered in defence, industrial, and commercial domains, and I’ve improved system reliability, reduced defects, and built maintainable solutions. I’m based in Devon, UK, hold active SC clearance, fluent in French, and hold a full UK driving license.

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Intermediate

Intermediate

Intermediate

Intermediate

Language

French

Fluent

English

Fluent

Work Experience

Senior Software Contractor at Raytheon

December 1, 2025 - Present

Designed and delivered components for a defence-sector training simulator; built WPF UI layer interfacing with a real-time physics engine; defined modular architectural boundaries and integration strategy; developed performance-sensitive components in a safety-critical environment emphasizing reliability and maintainability.

Independent Contractor at Stonepine Software

January 1, 2023 - Present

Delivered a full-stack Motorcycle Rally Platform (attendees ~150) with Stripe payments, dynamic booking, React frontend, Supabase backend, and serverless .NET back-end via AWS Lambda and API Gateway. Built a MAUI iOS app with live updates and push notifications; integrated Azure OpenAI for an AI-powered workshop assistant.

Independent Contractor - MAUI App Lead at Stonepine Software

January 1, 2023 - Present

Middle-earth Strategy Battle Game App: cross-platform MAUI application with real-time two-player synchronization using SignalR; secure data backup (MySQL + iCloudKit); authentication, API layer, PDF roster generation (Syncfusion) and live data sync features.

Senior Software Contractor at Dootrix

June 1, 2025 - August 1, 2025

Diagnosed and resolved live production defects using Sentry telemetry; traced issues end-to-end across platform-specific layers; proposed and prototyped an architecture that reduced coupling and increased testability; stabilised a large cross-platform production application.

Senior Software Contractor at Inductosense

October 1, 2024 - October 1, 2025

Architected .NET Core background Windows Service for secure client/server data synchronization, conflict resolution and versioned processing; delivered a MAUI Blazor interface for visualising and analysing high-volume digital scanner data; applied strict TDD (NUnit) throughout.

Senior Software Contractor - Kiosk & Booking at Hollywood Bowl

August 1, 2023 - October 1, 2024

Co-architected MAUI-based self-service kiosk and WinUI desktop booking system; defined clean communication flows between UI, services and Web API; delivered real-time booking updates across terminals using SignalR; achieved ~95% unit test coverage; contributed to React customer-facing website.

Senior Software Contractor at Hollywood Bowl

August 1, 2023 - October 1, 2024

Co-architected MAUI-based self-service kiosk and WinUI desktop booking system, defining clean communication flows between UI, services and Web API; delivered feature-rich kiosk applications streamlining customer check-in and food ordering across multiple countries (including Canada tax rules); implemented real-time booking sheet updates across all terminals using SignalR; achieved ~95% unit test coverage (NUnit) and contributed to a React customer-facing website.

Contract Software Developer at Stonepine Software

January 1, 2013 - December 31, 2023

Delivered multiple cross-platform Xamarin/MAUI apps, WPF systems and high-throughput sensor servers; led development of industrial sensor configuration and remote logging systems handling hundreds of connections per second; mentored junior developers and modernised legacy WinForms applications to WPF.

Various Roles at Earlier Roles

January 1, 2013 - December 31, 2023

Delivered multiple cross-platform Xamarin/MAUI apps, WPF systems and high-throughput sensor servers. Highlights include Royal Navy cadet training simulator (WPF + gRPC), industrial sensor configuration and remote logging systems, mentoring juniors and modernising legacy WinForms to WPF.

Senior Software Contractor at Various

January 1, 2013 - December 31, 2023

Delivered multiple cross-platform Xamarin/MAUI apps, WPF systems and high-throughput sensor servers. Mentored junior developers and modernised legacy WinForms applications to WPF.

Independent Contractor at Stonepine Software

January 1, 2025 - Present

Motorcycle Rally Platform: Designed and delivered full-stack web platform supporting ~150+ attendees for a large-scale live event. Built dynamic booking system with multiple ticket types, pricing models, accommodation options, Stripe payments and automated workflows. Developed responsive React frontend with Supabase backend plus admin tooling. Designed and implemented serverless backend services using AWS Lambda (.NET) and API Gateway, handling booking validation, payment workflows, and transactional operations for a live event website. Built and published companion iOS application using .NET MAUI with live updates, push notifications and real-user features. Integrated Azure OpenAI services to design and implement an AI-powered workshop assistant, enabling natural-language interaction with motorcycle mechanical data and improving user support capabilities.

Project Lead / App Developer at Stonepine Software

January 1, 2023 - Present

Middle-earth Strategy Battle Game App: Designed and released cross-platform MAUI application. Implemented real-time two-player synchronisation using SignalR and secure user data backup (MySQL + iCloudKit). Built authentication, API layer, PDF roster generation (Syncfusion) and live data sync features.

Various Roles at Multiple Employers

January 1, 2013 - December 31, 2023

Earlier roles delivering cross-platform Xamarin/MAUI apps, WPF systems and high-throughput sensor servers. Highlights include: building a Royal Navy cadet training simulator for Babcock (WPF + gRPC) featured in Navy News; leading industrial sensor configuration and remote logging systems; mentoring junior developers and modernising legacy WinForms to WPF.

Contractor at Various/Earlier Roles

January 1, 2013 - January 1, 2023

Delivered multiple cross-platform Xamarin/MAUI apps, WPF systems and high-throughput sensor servers; Royal Navy cadet training simulator for Babcock featured in Navy News; mentored junior developers and modernised legacy WinForms to WPF; supported hundreds of concurrent connections.