Senior .NET Developer — WinForms Modernisation (Remote)

Avanti Recruitment; Lancashire; Hybrid; GBP 65,000 - 75,000; Full time

Benefits offered by this job

25 days holiday

Job summary

Avanti Recruitment is seeking a senior developer to own and modernise a Windows desktop WinForms platform migrated to .NET 8. You will stay hands-on with C#/.NET, influence architecture and testing, and collaborate with leadership to shape API- and cloud-driven evolution.

The role is based near Heathrow, Colnbrook, with initial 1–2 weeks onsite onboarding, then mostly remote work with occasional office visits. Salary up to £75,000, 25 days holiday, pension and benefits included.

Qualifications

• Excellent hands-on development experience with modern C# and .NET.
• Meaningful commercial experience with WinForms.
• Commercial test-driven development experience using a test-first Red/Green/Refactor approach.
• Strong automated testing experience.
• Experience contributing to technical decisions and software design.
• Experience owning and modernising existing applications.
• Experience migrating WinForms apps to modern .NET (highly desirable).
• Exposure to Clean Architecture (highly desirable).
• Experience with API design and service-based architecture (highly desirable).
• React or JavaScript exposure (highly desirable).
• AI-assisted development or Python experience (highly desirable).

Responsibilities

• Take ownership of a business-critical WinForms platform migrated to .NET 8.
• Modernise an established desktop application using current .NET practices.
• Improve maintainability, automated testing and technical direction.
• Support the delivery of new business functionality.
• Contribute to software design, architecture and technical decisions.
• Collaborate with CTO, Head of Engineering and original author.
• Shape future architecture via APIs, cloud services and modern web tech.
• Remain hands-on with C#/.NET development.
• Influence technical direction and platform evolution with the team.
• Support CI/CD and testing practices for a WinForms app.

Skills

C#/.NET expertise

WinForms experience

Test-driven development

Automated testing

Technical decision making

Platform modernization

API design

JavaScript exposure

Python exposure / AI

React exposure

Tools

C#

.NET Framework

ASP.NET

Azure

REST

SQL

CI/CD

React

JavaScript

Python

Job description

Avanti Recruitment is seeking a senior developer to own and modernise a Windows desktop WinForms platform migrated to .NET 8. You will stay hands-on with C#/.NET, influence architecture and testing, and collaborate with leadership to shape API- and cloud-driven evolution.

The role is based near Heathrow, Colnbrook, with initial 1–2 weeks onsite onboarding, then mostly remote work with occasional office visits. Salary up to £75,000, 25 days holiday, pension and benefits included.