Senior Full Stack C# .NET Developer

WebX Systems Ltd.; United Kingdom; Remote; GBP 70,000 - 85,000; Full time

Job summary

WebX Systems Ltd. is seeking a Senior Full Stack .NET Developer to join their fully remote team. The successful candidate will be responsible for leading projects, enhancing applications, and migrating legacy systems to modern solutions, making a significant impact within a small, collaborative environment. A strong background in C# and .NET, along with excellent problem-solving and communication skills, is essential.

Benefits

Technical Growth

Autonomy in technical decisions

Career Advancement

Work-Life Balance

Professional Development Budget

Competitive Benefits

Qualifications

• 5+ years of experience in C# and .NET development.
• Proficiency with legacy and modern .NET technologies.
• Experience in application modernization and cloud solutions.

Responsibilities

• Lead projects from concept to deployment and maintain existing applications.
• Drive the migration of legacy systems to modern web platforms.
• Write clean, maintainable code and facilitate peer reviews.

Skills

C#

.NET Framework

WinForms

SQL Server

HTML

CSS

JavaScript

Blazor

Problem Solving

Communication

Education

Degree in Computer Science or related field

Tools

Redis

RabbitMQ

Docker

Azure

Job description

Senior Full Stack C# .NET DeveloperFully Remote (UK Residents Only)
About WebX Systems

At WebX, we specialise in technical publishing and content management solutions for the aerospace and defence sectors worldwide. Our flagship products—UltraCSDB, UltraAuthor, UltraXML , and UltraPortal—are used globally and combine proven legacy systems with cutting-edge, cloud-native innovations.

As a privately owned UK business, we take pride in delivering exceptional software and highly responsive support. Joining our close-knit team means your work has direct and meaningful impact. We work closely with customers to ensure our solutions meet their exact requirements. Join us on our journey to become the global leader in aerospace and defence content management.

Role Overview

We're looking for a proactive, experienced Senior Full Stack .NET Developer to help evolve our product suite. You’ll work across both legacy Windows desktop applications and modern web-based systems and help lead the transition toward cloud-native architecture. This role is perfect for someone who enjoys innovating within established environments while also driving forward new development.

Technology Stack

Legacy

• C#, .NET Framework, WinForms, WCF
• Client-Server Architecture, MS SQL Server

Modern

• .NET 9, Blazor, Minimal APIs
• Entity Framework, Redis, RabbitMQ
• Aspire (.NET), Cloud-Native development
  

Key Responsibilities

• Project Leadership – Lead projects from concept to deployment, collaborating with senior developers and the technical director to design and implement architectural and technical solutions.
• Full Stack Development – Maintain and enhance both legacy desktop applications and modern browser-based web apps.
• Legacy-to-Modern Migration – Help drive the migration from WinForms to Blazor-hosted cloud solutions.
• Code Quality & Testing – Write clean, maintainable, well-tested code, and conduct peer reviews.
• Problem Solving – Design robust, scalable solutions to complex challenges.
• Customer Collaboration – Communicate effectively with non-technical stakeholders to translate business needs into technical requirements.
• Continuous Improvement – Proactively refactor and optimise existing codebases; contribute to internal documentation.
  

Required Skills & Experience

• 5+ years of commercial experience in C# and .NET.
• Expertise in:
• .NET Framework and WinForms
• Modern .NET (.NET 9)
• SQL Server (including performance optimisation)
• Front-end tech (HTML, CSS, JavaScript)
• Proven experience with application modernisation, including migrating legacy WinForms applications to modern web platforms (Blazor preferred).

·Strong understanding of layered architecture and best practices in software design.

• Proven ability to deliver complex software projects independently.
• Strong analytical and problem-solving skills.
• Excellent written and verbal communication, with the ability to explain technical topics to business stakeholders.
• Degree in Computer Science or related field (or equivalent experience).
  

Bonus Points For

• Experience with Blazor and RESTful/API-first development
• Familiarity with Azure or other cloud platforms
• Understanding of .NET Aspire and containerisation (e.g. Docker)
• CI/CD pipelines, DevOps practices
• OAuth/OpenID Connect authentication
• Application modernisation or migration work
• XML/XSLT and publishing workflows
• Familiarity with ASD S1000D, ATA iSpec 2200, or related aerospace/defence standards
• Experience using AI-based coding assistants (e.g. Claude, ChatGPT, GitHub Copilot) to boost productivity and code quality.

What We Offer

• Salary: £70,000 – £85,000 depending on experience
• Technical Growth – Work across a diverse technology landscape, from legacy systems to cutting-edge cloud-native tools.
• Autonomy – Freedom to shape technical decisions and make a significant impact on product direction and architecture.
• Career Advancement – Opportunities to progress and grow as you help lead the next phase of our technology evolution.
• Work-Life Balance – Fully remote role with flexible working arrangements to support your productivity and well-being.
• Professional Development – Dedicated budget and support for ongoing training, certifications, and learning new technologies.
• Competitive Benefits – Workplace pension, annual leave that increases with tenure, and a supportive culture for professional growth.
  

Team & Culture

We’re a small, collaborative, and fully remote team. We value async-first communication and structured collaboration. Everyone’s contribution matters, and ideas are heard, tested, and implemented rapidly.

Interview Process

Introductory video call

Technical assessment (take-home or timed)

Technical interview with real-world problem-solving

Final interview with company leadership

Location

• UK-based applicants only
• Fully remote
• Equipment provided

Seniority level

• Seniority level

  Mid-Senior level

Employment type

• Employment type

  Full-time

Job function

• Job function

  Engineering and Information Technology

• Industries

  Software Development

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