Senior C# .NET Developer

Location: Remote-first, with weekly in-person meetings at our Derbyshire office Salary: £45,000–£65,000 depending on experience Contract: Permanent, full-time

Role overview

Glusoft is looking for a Senior C# .NET Developer to help design, build and improve large, data-driven software applications for our clients.

Our core work is the development of business-critical systems that manage, process and present important operational data. These applications support real business processes, integrate with client systems, and are used by customers and teams who rely on them every day.

This is a senior hands-on development role with significant ownership and influence. You will work directly on software that supports real business operations, solve meaningful problems for customers, and help shape the technical direction of the systems we deliver.

Rather than being limited to a small part of a product, you will be trusted to take ideas from concept through to production, make key technical decisions, and see the real-world impact of your work.

We are looking for someone who can do more than produce code. The right person will be able to analyse requirements, understand the wider architecture, identify risks, challenge poor technical decisions, and recognise when code is wrong, fragile, insecure or unsuitable for production.

Our technology stack

Our core development work is in C# and .NET, building data-driven applications, APIs, integrations and backend services. We also work with:

• MongoDB
• Angular or modern frontend web application development
• Amazon Web Services (AWS)
• Kubernetes
• Salesforce
• Native mobile applications on iOS and Android
• AI-enabled integrations and intelligent workflow solutions

You do not need experience with every part of our stack. We are primarily looking for a strong C#/.NET developer with solid problem-solving skills, good data/application design instincts and sound engineering judgement. Experience with the technologies above is beneficial, but we are happy to support the right person in developing those skills.

Working arrangement

You will work remotely most of the time, with a weekly in-person meeting at our Derbyshire office to collaborate with the team, shape priorities and keep delivery moving.

Because we meet in person every week, this role is best suited to someone who lives within approximately one hour's commute of our Derbyshire office and can attend these sessions reliably.

Large data-driven client applications

First and foremost, this role is about building and improving substantial software applications for clients.

Our systems typically involve data capture, data processing, reporting, workflow, integrations, user interfaces, APIs and operational tools. They need to be reliable, maintainable and fit for real-world use.

You will be involved in understanding client requirements, modelling data and processes, designing technical solutions, building application features, integrating with other systems, and improving existing platforms over time.

This may include:

• Building and maintaining business-critical C#/.NET applications.
• Designing APIs, services and integrations around client data.
• Working with MongoDB and other data stores.
• Building features that help users capture, manage, search, analyse and act on data.
• Integrating applications with third-party systems, CRMs, ERPs or client platforms.
• Improving performance, reliability and maintainability of existing systems.
• Supporting applications that are actively used in day-to-day business operations.
• Making pragmatic architecture decisions that balance quality, cost, risk and delivery.

We are looking for someone who understands that good software is not just about isolated features. It is about data, workflows, users, security, reliability, maintainability and the long-term shape of the system.

AI integration and intelligent client solutions

AI integration is an important and growing part of Glusoft's work, but it sits alongside and supports our core development of data-driven client applications.

We help clients use AI where it adds practical value to existing systems, workflows and data. Our focus is not on gimmicks, generic chatbots or throwaway prototypes. We are interested in rich, integrated AI solutions that connect properly with client applications, operational data, business rules and existing processes.

This may include:

• AI-powered features within larger business applications.
• Internal AI assistants that work with controlled business data.
• Customer-facing chatbots connected to appropriate systems and knowledge sources.
• Workflow automation that helps users process information and complete tasks.
• Document and data processing tools.
• Intelligent search, summarisation and analysis features.
• Integrations between AI services, databases, APIs, CRMs, ERPs and other client platforms.
• Tools that help users search, interpret, validate and act on business data.
• AI-enhanced reporting, decision support or operational workflows.

As part of this role, you may help design and deliver AI-enabled features and integrations that extend the applications we build for clients. The primary requirement is still strong software engineering: understanding systems, designing robust solutions, writing maintainable code and making good technical decisions.

We are looking for someone who can think about AI as part of a wider system. That means considering data access, permissions, security, reliability, auditability, user experience, error handling, human oversight and how the AI feature fits into the client's real workflow.

AI-related responsibilities

• Help design and integrate AI-enabled features into client applications and workflows.
• Build APIs, services and integrations that connect AI capabilities to operational data.
• Work with controlled data sources, business rules and existing client systems.
• Consider security, privacy, permissions, auditability, data quality and human oversight.
• Help clients move from AI ideas to maintainable production-ready solutions.
• Identify where AI can add genuine value and where a simpler software solution is more appropriate.
• Work with colleagues to design AI features that are useful, explainable and safe to operate.
• Help ensure AI-enabled systems are robust, testable and integrated properly with the wider application.

You do not need to be an AI specialist already. We are looking for a strong software engineer who is interested in applying AI capabilities within real business systems.

The right person will be curious about AI, but also technically disciplined. You should be able to think beyond a prompt or model response and consider the surrounding architecture, data flows, security boundaries, user experience and operational risks.

Key responsibilities

You will be involved across the full software development lifecycle, from understanding requirements and shaping technical designs through to development, testing, deployment and support.

Software development and delivery

• Build and maintain large data-driven applications using C# and .NET.
• Design reliable, maintainable and scalable software.
• Develop APIs, integrations and backend services.
• Work with business-critical systems used by real customers.
• Model data, workflows and business processes in software.
• Build features that help users manage, process, report on and act on data.
• Improve existing systems, code quality, performance and reliability.
• Debug, troubleshoot and resolve technical issues.
• Take ownership of technical work from design through to delivery.
• Review code for correctness, maintainability, security and architectural fit.
• Identify technical debt and help decide when and how it should be addressed.

Technical leadership and collaboration

• Contribute to technical direction, architecture and development practices.
• Make pragmatic technical decisions that balance quality, risk, cost and delivery.
• Work closely with colleagues and stakeholders to understand problems and deliver useful software.
• Explain technical trade-offs clearly to both technical and non-technical people.
• Support and mentor other developers where appropriate.
• Help improve how the team designs, reviews, tests and ships software.

Wider platform and integration development

• Work across other areas of our technology stack, including MongoDB, AWS, Kubernetes, Salesforce and native mobile development.
• Help integrate applications with client systems, third-party platforms and operational data sources.
• Help build AI-enabled features and intelligent workflow solutions where they support the wider client application.
• Contribute to patterns and practices for delivering secure, maintainable and integrated AI solutions.

Requirements

Essential experience

You should have a minimum of 7 years' commercial software development experience, along with a degree or equivalent commercial experience.

You should have strong commercial experience with:

• C# and the .NET ecosystem.
• Building and maintaining business-critical software.
• Designing clean, maintainable and scalable backend systems.
• Developing data-driven applications.
• Web APIs, integrations or service-based applications.
• Working with databases and data models.
• Debugging, troubleshooting and improving existing systems.
• Writing clean, maintainable code.
• Reviewing code and recognising when an implementation is flawed.
• Understanding software architecture and how individual changes affect a wider system.
• Considering security, data protection, access control and operational risk when building software.
• Working with source control and modern development workflows.
• Taking ownership of technical decisions and delivery.
• Angular or modern frontend web application development.

We are looking for someone who can bring experience, judgement and pragmatism — not just write code, but help us make good technical decisions.

Desirable experience

Experience with any of the following would be useful, but is not essential:

• MongoDB or another NoSQL/document database.
• Amazon Web Services or another cloud platform.
• Kubernetes, Docker or containerised application development.
• Salesforce development.
• Native iOS or Android development.
• ASP.NET / ASP.NET Core.
• CI/CD pipelines.
• Agile or iterative delivery.
• AI integration, automation, workflow tools or data processing.
• Working with AI APIs, language models or intelligent search.
• Designing integrations around structured and unstructured data.
• Secure development practices.
• Architecture, technical design or solution design.
• Working in a smaller team where developers have broad responsibility.

You do not need to tick every box. If you are a strong C#/.NET developer who enjoys building data-driven applications and working across different areas of a product, we would still like to hear from you.

About you

You are likely to be a good fit if you:

• Enjoy taking ownership rather than waiting to be told every step.
• Can balance technical quality with commercial reality.
• Communicate clearly with both technical and non-technical colleagues.
• Are comfortable working remotely while staying visible and collaborative.
• Like improving systems, not just adding features.
• Enjoy working with data-driven applications, workflows and integrations.
• Can analyse a problem before jumping into implementation.
• Can explain why a piece of code is correct, incorrect, risky or hard to maintain.
• Think about architecture, security, testing and long-term maintainability.
• Are willing to challenge proposed solutions when they are not right.
• Are interested in AI and automation as ways to enhance real business applications.
• Can think about how AI features integrate with data, permissions, workflows and user needs.
• Are curious about new technologies, but pragmatic about how they are used.
• Want to have genuine influence in a smaller, focused team.
• Care about building software that is practical, reliable and maintainable.

This role is not suited to someone who simply wants to generate code and move on. It is suited to someone who wants to understand the problem, think through the design, use the right tools, and take responsibility for the quality of the final result.

What we offer

• Salary of £45,000–£65,000, depending on experience.
• Remote-first working.
• Weekly in-person collaboration at our Derbyshire office.
• A senior role with real technical influence.
• Direct access to decision-makers and stakeholders.
• Varied, meaningful development work.
• The opportunity to build large data-driven applications for real client needs.
• Exposure to a modern and varied technology stack.
• Opportunity to develop skills in cloud, containerisation, Salesforce, native mobile development and AI integration.
• The chance to help shape rich, integrated AI solutions that support real client systems and workflows.
• A practical, supportive team environment.
• The opportunity to improve systems, processes and technical standards.

Working pattern

This is a remote-first role, with one in-person meeting each week at our Derbyshire office to support collaboration and decision-making.

Why join Glusoft?

If you are looking for a role where your work has visible impact, your ideas are heard, and you can take real ownership, this is an opportunity to do exactly that.

At Glusoft, senior developers are trusted to solve problems, influence decisions and help shape the products and platforms we build. You will work closely with stakeholders, understand the outcomes clients are trying to achieve, and deliver software that makes a measurable difference to how their businesses operate.

You will have the opportunity to:

• Build large, data-driven applications that support real client operations.
• Own projects and technical solutions from concept through to delivery.
• Influence architecture, engineering standards and technology choices.
• Build software that is used daily by real customers and operational teams.
• Deliver improvements that increase efficiency, reliability and business value.
• Integrate systems, data sources and platforms into useful client solutions.
• Help organisations adopt AI and automation in practical, responsible ways where they support the wider application.
• Design rich AI-enabled features that work with real data, permissions, workflows and client systems.
• Work across a varied technology landscape rather than being confined to a single product area.

Because we are a focused, growing team, your contribution will be visible. You will have direct access to decision-makers, the freedom to suggest better approaches, and the ability to see the outcomes of your work in production.

You will not be expected to know every technology we use from day one. What matters is that you are a strong C#/.NET developer who can take ownership, apply sound engineering judgement and deliver meaningful results.

We are interested in people who understand data, architecture, security, testing, maintainability and the responsibility that comes with building production software. For AI-enabled work, we are looking for people who can think beyond the model itself and understand how intelligent features need to integrate safely and usefully into real client systems.

If you want autonomy, variety, technical influence and the opportunity to build software that creates real-world impact, we would like to hear from you.

How to apply

Send us your CV and a short note about:

• The kinds of systems you have worked on.
• Your experience with C#/.NET.
• An example of a technical decision you influenced or a difficult problem you solved.
• How you approach code quality, architecture and security.
• What interests you about building data-driven applications and integrated client systems.
• What you are looking for in your next role.

We are more interested in practical ability, good judgement and the way you approach problems than in ticking every possible technology box.

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