Senior Backend Engineer (Python)

Benifex Limited; Greater London; Hybrid; GBP 70,000 - 110,000; Full time

Benefits offered by this job

Tech setup

Learning budget

Flexible work

25 days holiday

Birthday off

Wellbeing days

Healthcare plan

Employee assistance

Income protection

Life insurance

Pension

Parental leave

Benifex card

Job summary

Benifex Limited, a fast-growing UK technology company, seeks a backend engineer to design and build features for Brain, our AI-powered product. You will leverage Python and .NET, work with LangChain/LangGraph, and collaborate with remote teams to ship robust APIs and services.

You will apply AI-native development practices, own delivery quality, and contribute to AI security, observability, and performance improvements across the stack. Flexible UK-based hybrid work is offered.

Qualifications

• Commercial GenAI experience (6+ months) including MCP and agent orchestration.
• Ability to deliver features end-to-end with initiative and minimal direction.
• Strong backend development experience with Python and SQL.
• Familiarity with AI coding assistants and AI native engineering practices.
• Experience with containerisation and CI/CD pipelines.

Responsibilities

• Design and build features for our flagship AI product Brain.
• Understand the Benefits product and APIs using Python/.NET experience.
• Own the quality of what you ship; test, fix defects, learn and improve.
• Write clear, maintainable code and provide feedback on PRs.
• Improve performance, security, and accessibility of systems.

Skills

Python

.NET

SQL

GenAI

CI/CD

AI security

Debugging

Production support

Tools

LangChain

LangGraph

Google ADK

Kubernetes

Google Pub/Sub

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 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

Great benefits:

• 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 quarter in our UK HQ and you need to be based in UK, Ireland, Germany or the Netherlands
• 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)
• Pension scheme
• Enhanced parental leave package - 26 weeks fully paid maternity leave and 4 weeks fully paid paternity leave
• £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!

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

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 Python / .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.

Tech stack

Python, LangChain, LangGraph, Google ADK, .NET, SQL, GCP, MSMQ (moving to Google Pub/Sub), Kubernetes.

What are we looking for?

• 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.

• Solid commercial experience in backend development with Python and confidence working with SQL.

• 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 agentic orchestration, 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:

• Working with A2A integrations.
• Experience with messaging systems like Google Pub/Sub and caching solutions like Redis.
• Cloud experience, particularly deploying and scaling applications (GCP especially welcome).
• Familiarity with observability tools for monitoring, logging and alerting (e.g. Langfuse, Grafana).
• Mentoring or supporting more junior engineers.

Our interview process

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