Senior Developer - Remote/ Yeovil

About Arc:
Arc is a leading IT Managed Services Provider (MSP) based in the UK, delivering innovative and reliable IT solutions to businesses across various industries. With a strong reputation for excellence, we offer a range of services, including IT support, hybrid cloud solutions, cybersecurity, infrastructure management, PowerApps and AI. Our team is dedicated to delivering outstanding customer service and technical expertise to help businesses succeed.

Role Overview:

As Senior Developer, you’ll lead the design, development and maintenance of our flagship intranet-in-a-box product and its roadmap. You’ll build scalable, efficient SPFx solutions using TypeScript and React, and integrate backend services through Azure Functions with .NET and C#, setting the standard for coding quality, performance and user experience.

The role is as much advisory as it is hands-on: you’ll guide the business on the future direction of the product, combining the best of Microsoft technologies with what our clients actually need — in a way that is valuable to end users, scalable and economically supportable. Working with the customer success team, you’ll turn end-user insight into product decisions. The immediate priority is integrating Microsoft 365 Copilot and AI services into the platform.

We expect our developers to work AI-First. You will use modern AI coding tools, Claude, GitHub Copilot and similar to accelerate delivery without compromising quality, and help set the standards for how the wider team uses them. That means being equally comfortable with fast, exploratory “vibe coding” to prototype and prove ideas, and with the disciplined, controlled deployment practices code review, automated testing and staged CI/CD releases that get AI-assisted work safely into production. Please note this role is primarily remote with occasional travel to our Arc offices (London, Basildon, Yeovil, Yateley)

Key Responsibilities:

• Lead the full software development lifecycle for our flagship intranet-in-a-box product — planning, design, coding, testing and maintenance of key components.

• Build high-quality, reusable and scalable web parts and extensions using the SharePoint Framework (SPFx), TypeScript and React.

• Develop and integrate serverless Azure Functions using .NET and C# to support the product’s backend services.

• Integrate Microsoft 365 Copilot and AI services into the platform as the next major phase of development.

• Shape the product roadmap, advising the business on future direction and on where Microsoft technologies best meet client needs.

• Maintain and manage CI/CD pipelines, ensuring consistent, high-quality releases across all environments.

• Write clean, maintainable and efficient code, adhering to industry best practice and agreed coding standards.

• Work closely with business sponsors, the customer success team, designers, QA testers and fellow developers to deliver innovative, user-centric solutions.

• Keep performance, scalability and security considerations front of mind throughout development.

• Maintain clear, concise technical documentation to support efficient onboarding, handover and knowledge transfer.

• Stay current with industry trends, emerging technologies and tooling across Microsoft 365, SPFx and Azure.

• Hands-on experience with agentic AI coding tools (Claude Code, GitHub Copilot or similar) driving the full edit–test–review loop.

• Comfort writing effective prompts and context for AI tools, and reviewing/validating AI-generated code before it ships.

• Experience defining or contributing to reusable AI assets custom agents, skills, prompt libraries or coding standards for AI-assisted work.

• Awareness of safe AI-in-the-SDLC practices, code review, automated testing and staged CI/CD for AI-generated changes.

• Familiarity with integrating AI/LLM services into applications (M365 Copilot, Azure OpenAI or equivalent APIs).

Required Skills & Experience:

• Front-end skills: strong commercial experience with JavaScript, TypeScript, React and the SharePoint Framework (SPFx).

• Back-end skills: strong working knowledge of .NET and C#, including serverless development with Azure Functions.

• General technical skills: Git, CI/CD, GitHub / Azure DevOps and SQL databases.

• Experience leading development projects end to end, owning technical decisions and code quality.

• Solid understanding of the Microsoft 365 ecosystem — SharePoint Online, Teams, Power Apps and Po…