Senior UK .NET Developer – Long-Term System Support + Dev

We are looking for an experienced UK-based senior .NET developer to take long-term ownership of a business-critical CRM & Finance platform.

This is not a one-off task. We want a long-term partner who can first familiarise themselves with the system and stabilise it, then provide full ongoing support and further system development.

We are actively replacing an existing slow and ineffective support arrangement and are keen to work with someone professional, proactive and reliable.

Phase 1 – Initial Audit, Familiarisation & Bug Fixing

The first phase will be a paid engagement to:

• Set up a full offline / local development environment
• Review the codebase, database and overall architecture
• Identify and fix priority bugs and long-standing issues
• Improve system stability and performance
• Produce a short stabilisation and improvement plan

This phase allows you to fully understand the platform and demonstrate ownership before moving into long-term support.

Phase 2 – Full Ongoing Support & Further Development (Long-Term)

After stabilisation, this becomes an ongoing hourly role providing both live system support and further development, including:

• Full production support when bugs or system issues arise
• Rapid diagnosis and fixing of live problems
• Ongoing performance monitoring and optimisation
• Enhancements and new feature development
• Refactoring and gradual modernisation
• Safe testing and controlled deployment into the live environment

We expect regular monthly work and a long-term working relationship.

Technology Stack

• VB.NET and C#.NET (mixed legacy and newer code)
• SQL Server Express (stored procedures, LINQ, optimisation)
• jQuery, NuGet packages, PDF export module
• Hosted on AWS (Windows Server 2019)
• Source control in Bitbucket

Two tightly integrated applications (CRM + Finance) sharing a central database.

Who We’re Looking For

This role is only suitable for a senior UK-based developer who:

• Has strong experience with C#.NET / VB.NET and SQL Server
• Has proven experience supporting live, business-critical systems
• Is confident diagnosing and fixing production issues quickly
• Is comfortable owning and evolving a complex legacy platform
• Communicates clearly and works reliably long-term

Experience with AWS / Windows hosting is a strong advantage.

Budget & Engagement

• Engagement via PeoplePerHour
• Hourly rate: £60 – £75 per hour (depending on experience)
• Phase 1 expected to be a short initial contract (audit + stabilisation)
• Phase 2 is an ongoing hourly support & development role with regular monthly work

How to Apply

Please include:

• Confirmation that you are UK-based
• Relevant experience with legacy .NET systems and live production support
• Your hourly rate
• Availability per week / month
• Brief outline of how you would approach the initial audit and stabilisation phase