Senior Backend Engineer (.NET & Python)

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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 UK. 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? ??

• Grow : 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
• Top 10 Employer, Sunday Times Best Places to Work Awards
  
• Work for a profitable, fast-growing market leader in the online reward and benefits space
• 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

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
?? £70,000 - £90,000

?? 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!

Role Overview ??
We are looking for a Software Engineer with strong .NET and Python expertise and hands-on GenAI experience to help build and evolve Brain, Benifex's flagship AI platform. In this role, you will design, develop and deliver high-quality backend solutions that combine modern AI technologies with our established benefits platform. You will work closely with Product, Design and Engineering colleagues in a collaborative, distributed environment while contributing to our AI-first software development lifecycle. This is an opportunity to take ownership of impactful features, strengthen platform reliability and help shape the future of AI-native engineering at Benifex.

Responsibilities ??

• Design and build features for our flagship AI product, Brain - where Reward Directors can speak to and access a wealth of industry knowledge on what benefits are most suitable for their employee population
• You’ll use your background as a .NET engineer to understand our Benefits product and APIs
• 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.

What are we looking for? ??

• Solid commercial experience in backend development with C#.NET and Python , and confidence working with SQL .
• Commercial production GenAI experience (6 months+) including experience using MCP, orchestrating multiple agents, RAG based solutions, evals and agentic observability (Langfuse).
• An advocate for AI security and responsible AI
• 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

• Experience with Kubernetes, GCP, Google Pub/Sub, Kafka or Redis.
• Familiarity with Langfuse, Grafana, Prometheus or Terraform.
• Experience mentoring or supporting other engineers.

Even if you don't meet all of the requirements for this role, we encourage you to apply! We are looking for talented and passionate individuals who are eager to learn and grow.

Our interview process
?? Initial informal call with the Talent team

? Interview with our Engineering Manager 30-45 min

?? Technical Interview - 60 min

?? Final interview with VP of Engineering - 30-45 min

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.

Location
London

Remote status
Hybrid