Backend Engineer (.NET)

Benifex Limited; Southampton; On-site; GBP 45,000 - 75,000; Full time

Benefits offered by this job

50 monthly Benifex card allowance

Flexible work setup in UK/Ireland

25 days holiday + bank holidays

Healthcare cash plan

Job summary

Benifex Limited is seeking a backend engineer to design and build features for our Benefits product using C#.NET and .NET Core. You will own tasks end-to-end with support from a talented team, ensuring high quality, accessibility, performance and security.

You’ll work within an AI first SDLC, collaborating with Product, Design and Engineering to deliver cohesive solutions and contribute to production stability while growing skills in Kubernetes, SQL and cloud technologies.

Qualifications

• Solid commercial backend experience with C#.NET and .NET Core, and confident with SQL.
• End-to-end feature delivery with minimal direction and proactive problem solving.
• Awareness of performance, security and testability considerations.

Responsibilities

• Design and build features for our Benefits product in C#.NET and .NET Core, breaking them down into tasks with support from your team.
• Own the quality of what you ship, test your work, fix defects, and continually improve processes.
• Write clear, well-structured code following our conventions and provide feedback on PRs.
• Improve maintainability, performance, accessibility and security of the codebase.
• Contribute to system stability and on-call readiness with senior engineers.

Skills

C#.NET

.NET Core

SQL

CI/CD

Kubernetes

AI assisted development

Tools

Kubernetes

Job description

Who are Benifex?

We are a fast-moving technology company, and one of the most successful providers of online reward and benefits solutions in the world. We believe that everyone deserves an exceptional experience at work, every day, and build workplace technology that makes this happen. Benifex’s mission is to build remarkable experiences that employees love. Today Benifex supports more than five million employees in over 3,000 organisations across more than 100 countries. To help us on our quest to be the best, we need brilliant people on board and that’s where you come in.

Why should you apply?

• Growth: You'll own features end-to-end on a key product, with senior engineers alongside you to help you break down bigger problems and grow your scope.
• A clear path forward: We have published Engineering Career Pathways from Associate to Principal, so you know exactly what good looks like at your level and what the next step looks like.
• Technology: AI first by default, we're building our SDLC around AI Assisted engineering, and you'll be learning and shaping this alongside the rest of the team, not inheriting a finished playbook.
• Team: Work with a talented, experience group of engineers dedicated to building high quality product for our users.
• Sunday Times Best Place to Work 2025 and Best Large Tech Company to Work for 2025
• Work for a profitable, fast-growing market leader in the online reward and benefits space

Role Overview

Our Engineering department is building out a brand new team to focus on how we scale our platform and onboard customers, with this role being a key part of that team. This is an ideal opportunity to have real impact and learn from a super talented team of Senior Engineers working alongside you.

Please note we are unable to offer visa sponsorship and require to people to be based in the UK or Ireland for this position.

Great Benefits

• £45,000-75,000
• Tech setup of your choice (MacBook Pro or equivalent, monitors, etc.)
• £/€800 annual learning budget, plus two hours per week as ‘Focus Fridays’.
• Flexible work – choose a working setup that works for you, our only ask is to see you once a month in the office and you must be based in the UK or Ireland.
• Full access to our comprehensive benefits package, including discounts from hundreds of high street brands, salary sacrifice schemes across Finance, Health, Tech, and more
• 25 days holiday plus your local bank holidays
• Your birthday off
• Two half day wellbeing days
• Healthcare cash plan to cover the costs of day-to-day healthcare
• Employee Assistance Plan 24/7 365 support
• Income Protection (75%) and life assurance (4x salary)
• Referral bonuses
• Enhanced parental leave package - 26 weeks fully paid maternity leave and 4 weeks fully paid paternity leave
• Work from Anywhere policy for 90 days
• Buy and Sell scheme for holidays
• £50 monthly allowance to spend on whatever takes your fancy, your very own Benifex card will be topped up at the start of each month!

Responsibilities

• Design and build features for our Benefits product in C#.NET and .NET Core, breaking them down into tasks with support from your team.
• Take ownership of the quality of what you ship, testing your own work, fixing defects, learning from them, and improving how the team works.
• Write clear, well-structured code that follows our conventions, and give clear, actionable feedback on pull requests.
• Improve the quality and maintainability of the code you touch, applying good practice around accessibility, performance and security.
• Contribute to the stability of our systems.
• Strengthening alerts and runbooks, improving observability, and helping resolve production issues and incidents alongside a senior engineer.
• Work with Product, Design and Engineering colleagues to make sure what you build lands the right outcome, and proactively share progress.
• Work effectively with remote teams, including engineers from Java Spring Boot backgrounds, to deliver cohesive solutions.
• Support the onboarding of new engineers.
• Use and help evolve our AI assisted development practices as part of Benifex's AI first SDLC.
• Tech stack: .NET, SQL, GCP, MSMQ (moving to Google Pub/Sub), Kubernetes

What are we looking for?

• Solid commercial experience in backend development with C#.NET and .NET Core, and confidence working with SQL.
• A track record of delivering features end-to-end. You make steady progress without needing constant direction, unblock yourself where you can, and know when to ask for help.
• Good instincts for clean, maintainable code and awareness of non-functional concerns like performance, security and testability.
• Comfortable debugging and diagnosing issues in a running system, and interested in understanding how things behave in production.
• Exposure to containerisation and CI/CD pipelines; you don't need to have owned them, but you should be able to work within them and want to go deeper.
• Awareness of modern architectural patterns such as microservices and event-driven systems.
• Collaboration: you communicate openly, work well with cross-functional and remote colleagues, and bring clarity through documentation and proposals.
• Problem-solving: a resourceful approach to complex challenges, and the persistence to work through ambiguity.
• AI Assisted Development: practical, hands-on experience working with AI coding assistants (Claude Code, Copilot, Cursor, etc.) as part of your development workflow.
• AI Native Mindset: genuine interest in AI Native engineering practices, and a desire to help shape how a team works with AI rather than just consume it.

Bonus Points For

• Hands-on experience with Kubernetes in a production environment.
• Experience with messaging systems (Pub/Sub, MSMQ, Kafka) or caching solutions like Redis.
• Cloud experience, particularly deploying and scaling .NET applications (GCP especially welcome).
• Familiarity with observability tools for monitoring, logging and alerting (e.g. Grafana, Prometheus).
• Exposure to IaC tools such as Terraform.
• Experience working on legacy systems or gradually breaking apart a monolith.
• Mentoring or supporting more junior engineers.

Our interview process

Benifex understands the need to have a fast and efficient process, the below will all be completed in the shortest time possible.

• Initial informal call with the Talent team
• Interview with our Engineering Manager 30 min
• Technical Task
• Technical Interview - 60 min
• Final interview with VP of Engineering - 30-45 min

We are an equal opportunity employer and value diversity at our company. We do not discriminate on the basis of race, religion, colour, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status.

We are committed to creating a diverse and inclusive workplace where everyone feels welcome and respected. We believe that diversity and inclusion are essential to our success, and we are proud to be an equal opportunity employer.

We are a proud member of the Disability Confident employer scheme.

If you require any reasonable adjustments at any stage during the recruitment process, please let us know with your application.