Senior Software Engineer

What if you could combine challenging software engineering with the opportunity to make a genuine difference to healthcare?

At One Advanced, we're evolving Vision, a large-scale clinical practice management system used by GP surgeries and healthcare clinics. Thousands of clinical users rely on our software to support patient care, making reliability, quality and innovation essential.

We're looking for an experienced Senior Software Engineer to help shape the future of this mission-critical product. You'll work across a complex, established codebase, modernising technology, developing new capabilities and using agentic AI tools to transform how we build and test software.

Working with C++, COM and C#/.NET, you'll tackle substantial engineering challenges while helping move Vision towards a more modern, maintainable architecture. It's an opportunity to combine strong engineering fundamentals with emerging AI-enabled development practices and see the real-world impact of your work.

#LI-DG1

• Develop, maintain and enhance Vision across a complex codebase spanning C++, COM and C#/.NET.
• Diagnose challenging issues and improve system reliability, performance, maintainability and test coverage.
• Support the modernisation of legacy C++ and VB6 functionality towards modern .NET solutions.
• Work with SQL databases, COM interop and established data access technologies.
• Contribute to new web-based workflows through our IQHealth platform, improving experiences for GP practices and clinical users.
• Use agentic AI development and testing tools to accelerate engineering workflows, explore solutions and improve software quality.
• Review and validate AI‑generated code, applying sound engineering judgement to ensure changes are secure, reliable and appropriate for a clinical environment.
• Develop and maintain integrations with NHS systems and relevant healthcare standards.
• Contribute to technical design, code reviews and automated testing, collaborating with Product and QA teams to deliver effective solutions.

Must Have:

• Commercial experience developing complex software using MS C++ and C#/.NET.
• Experience with Windows desktop applications, ideally Windows Forms, and a strong understanding of maintaining and evolving established systems.
• Experience working with large codebases, diagnosing complex issues and understanding dependencies across application components.
• Solid SQL and relational database development skills;
  PostgreSQL experience is preferred.
• Experience using Visual Studio and MSBuild in a commercial development environment.
• An understanding of COM, OLE and interoperability concepts.
• An understanding of Windows APIs.
• A commitment to clean, maintainable code, appropriate testing and high engineering standards.

Highly Desirable:

• Experience with COM‑based systems, VB6 or  and legacy modernisation.
• Practical experience with agentic AI development tools, AI coding assistants or AI‑enabled testing.
• Curiosity about AI‑assisted software engineering and the ability to critically assess AI‑generated code.
• Experience in healthcare, regulated or safety‑critical software environments.
• Knowledge of NHS integrations, clinical systems or SNOMED CT.
• Experience with unit testing frameworks and Ranorex or comparable testing frameworks.
• Experience navigating large solutions with many interconnected projects.
• Familiarity with Git or Perforce, Jira and Confluence.

Success Measures

• Deliver high-quality software that meets requirements and minimises post‑release defects.
• Improve system reliability, maintainability and automated test coverage.
• Contribute to modernisation initiatives that support Vision's long‑term evolution.
• Use AI‑enabled development and testing to improve productivity without…