Senior C# Developer

Avanti Recruitment; Northampton; On-site; GBP 80,000 - 100,000; Full time

Job summary

A long-established UK organisation is seeking a Senior C# Developer to join its internal IT team. This full-time role involves designing and developing internal business applications, mentoring junior developers, and ensuring system reliability. The ideal candidate should have strong experience with C#, WinForms, and SQL Server, along with a collaborative approach and problem-solving skills. The position is fully on-site in Northamptonshire and offers a stable, long-term work environment with competitive benefits.

Benefits

Competitive salary

Paid overtime

Company pension scheme

Private healthcare

Life insurance

24 days holiday plus bank holidays

Qualifications

• Strong commercial experience with C#.
• Experience working with WinForms or desktop applications.
• Solid database experience (SQL Server or similar).
• Strong problem-solving and analytical skills.

Responsibilities

• Design, develop, and maintain internal business applications.
• Enhance and refactor existing systems for performance and reliability.
• Work closely with users to understand requirements and usage.
• Mentor junior developers and support code reviews.

Skills

C#

WinForms

SQL Server

Legacy Systems

Analytical Skills

Collaboration

Job description

Overview

SENIOR C# DEVELOPER

Location: West Northamptonshire

Working Pattern: Full-time, 100% on-site

A long-established, privately owned UK organisation is looking to hire a Senior C# Developer to join its internal IT team. This is a hands-on, senior role working on business-critical, on-premise systems that support day-to-day operations across the company.

This is an opportunity to work in a stable, long-term environment where quality, reliability, and doing things properly are genuinely valued.

Responsibilities

• As a Senior C# Developer, you will play a key role in the design, development, and ongoing improvement of internal software applications.
• You will be involved across the full software lifecycle and will have real influence over technical decisions and standards.
• This is not a narrow coding role. You will work closely with users and stakeholders, contribute to architecture, mentor junior developers, and help modernise legacy systems.

Key Responsibilities

• Design, develop, and maintain internal business applications
• Enhance and refactor existing systems for performance and reliability
• Contribute to architectural decisions and best practices
• Work closely with users to understand requirements and usage
• Debug, troubleshoot, and optimise applications
• Mentor junior developers and support code reviews
• Create and maintain technical documentation

Technology Environment

• C#
• WinForms desktop applications
• SQL Server (Oracle also used)
• On-premise systems
• Some legacy Delphi applications (being gradually rewritten)
• Delphi experience is a bonus, not a requirement.

What We Are Looking For

• Strong commercial experience with C#
• Experience working with WinForms or desktop applications
• Solid database experience (SQL Server or similar)
• Strong problem-solving and analytical skills
• Collaborative approach and good communication skills
• Comfortable working in a traditional, long-established business
• Able to commute daily to a West Northamptonshire office
• This role is fully on-site and not suitable for remote or hybrid working.

Working Hours & Benefits

• Standard working hours: 9:00am - 5:30pm
• 7.25 working hours per day with a longer lunch break
• Competitive salary, flexible for the right candidate
• Paid overtime
• Company pension scheme
• Private healthcare for the employee
• Life insurance
• 24 days holiday plus bank holidays
• Additional holiday with length of service

Interview Process

• Two-stage interview process
• Short practical C# exercise (approximately 30 minutes)
• Focus on real-world experience rather than theory

Why Apply?

• Long-term stability and job security
• Family-owned business with a strong culture
• High-trust environment and visible impact
• Quality-focused development with realistic timescales
• Opportunity to influence systems and technical direction