Senior .NET Engineer

Avanti Recruitment; Greater London; Hybrid; GBP 63,000 - 77,000; Full time

Benefits offered by this job

Pension

Holiday allowance

Employee benefits

Job summary

Avanti Recruitment is partnering with an established software business to modernise a core platform. They seek a Senior Fullstack .NET Developer with strong React experience to build scalable services and APIs.

You'll stay hands-on with C#/.NET, contribute to architecture decisions and test-first development. The role is remote-first with occasional in-person collaboration in West London; salary up to £70,000 plus pension and benefits.

Qualifications

• Strong C#/.NET experience with hands-on development.
• Proficient in React frontend development.
• Extensive TDD and automated testing experience.
• Experience contributing to architecture and technical decisions.
• Ability to work independently and take ownership.
• Cloud platforms experience would be useful.

Responsibilities

• Build and maintain applications using C#/.NET and modern services.
• Design REST APIs and develop frontend using React.
• Modernise established architecture and improve platform maintainability.
• Increase automated test coverage and code quality.
• Contribute to software design and architectural decisions.
• Work in a test-first development environment.
• Support existing systems while helping build future replacements.
• Collaborate across engineering teams to drive technical direction.

Skills

C#/.NET

React

TDD

REST APIs

CI/CD

Architecture/Design decisions

Ownership of technical problems

Job description

Avanti is working with an established software business that is investing heavily in the modernisation of one of it's core platforms and is looking for a Senior Fullstack .NET Developer with strong experience in React.

This is a hands on engineering role where you'll help evolve an established business-critical application into a more modern, scalable architecture.

The focus will be on improving the underlying platform, building modern services and APIs, increasing automated test coverage and gradually moving functionality towards a modern web-based frontend.

You'll remain very hands on with C#/.NET development while also contributing to software design, architecture and technical decisions across the wider engineering team.

The business places a strong emphasis on the engineering quality, automated testing and test-first development, so strong TDD experience is essential.

What you'll be doing

• Building and maintaining applications and services using C# and modern .NET
• Designing and developing REST APIs
• Developing frontend functionality using React
• Helping modernise an established application architecture
• Improving automated test coverage and overall code quality
• Working in a test-first development environment
• Contributing to software design and architecture decisions
• Improving platform maintainability, scalability and long-term technical direction
• Supporting existing systems while helping build their future replacement

Technology Environment

• C# / .NET 8
• REST APIs
• React
• SQL Server
• Automated testing
• TDD
• CI/CD
• Cloud technologies

Essential Skills

• Strong C#/.NET
• React
• TDD
• REST APIs
• CI/CD knowledge
• Experience contributing to architecture / design and technical decisions
• Ability to work independently and take ownership of technical problems

Experience with cloud platforms, legacy application modernisation or AI-assisted development would be useful.

Working arrangement

The role is remote first, with some initial time spent with the team during onboarding, and occasional in person collaboration thereafter (West London / M4 corridor) – costs covered.

Interview process

The process will involve an initial video call which will be a technical discussion, followed by a final-stage video interview including a practical coding element following TDD.

Package

Salary up to £70,000, plus pension, holiday allowance and additional employee benefits.