Software Engineer

What began as a single product in one market has rapidly evolved into a multi-product, multi-territory platform powering every stage of pricing and underwriting. AI is at the core of what we do - from building the world’s first domain-specific AI peer programmer for insurance (think GitHub Copilot with a PhD in actuarial science) to shaping agentic workflows that reinvent how this industry operates.

What makes hx different is the people who build it. Here, impact isn’t tied to title or tenure; it’s defined by the challenges you take on and the discipline you bring. Surrounded by peers who stretch you, you’ll do the best, hardest work of your life in a company engineered to endure.

If that sounds like you, join us in building what comes next.

About the Kernel team

The Kernel team sits at the core of hx’s platform, building the execution engine that underpins how customer models are evaluated, validated, and run safely at scale. Their work directly enables hx Renew and future products to make correct, performant, and explainable decisions in high-stakes environments.

Within the team, engineers work on deeply technical system problems spanning execution, concurrency, memory management, and observability. The focus is on building a robust, modular engine that can evolve over time without compromising correctness or performance.

About the Role

As a **Software Engineer **in the Kernel team, you will own meaningful parts of this critical system end to end, contributing production code, improving architecture, and partnering closely with adjacent teams to ensure the engine meets real product and customer needs.

Key Responsibilities:

• Designing and delivering backend features in the Kernel execution engine that improve correctness, performance, and reliability for customer model runs at scale.
• Strengthening a clean, modular Kernel architecture that is easy to understand, test, and safely evolve over time.
• Building automated tests and observability for complex execution scenarios, enabling faster detection, diagnosis, and resolution of production issues.
• Partnering with adjacent engineering teams to shape Kernel behaviour and interfaces, providing clear technical input and following through to delivery.
• Owning work from design through rollout and monitoring, balancing immediate product needs with long-term system sustainability.
• Demonstrating hx values by proactively identifying risks, collaborating constructively, and taking full accountability in a critical core-platform area.

Requirements:

• Built and shipped backend systems in a polyglot production environment, working across languages such as Rust, Python, or C/C++, and choosing the right tool for the problem.
• Either used Rust in production systems, or demonstrated strong systems experience in C/C++ or Python with clear evidence of learning and adopting new languages quickly (you will be upskilled in Rust if you're not familiar).
• Delivered backend features where correctness, performance, and resource efficiency were critical, and improved systems based on real production behaviour.
• Applied solid systems thinking around execution, concurrency, and memory or resource management in real-world backend services.
• Designed and implemented effective testing and observability that made complex backend behaviour understandable, debuggable, and safe to evolve.
• Owned work end-to-end from design through rollout, monitoring, and iteration, collaborating closely with peers and raising risks early.

You’re unlikely to thrive here if

• You prefer highly predictable work and feel uncomfortable operating in ambiguous, evolving problem spaces.
• You optimise for shipping quickly at the expense of correctness, maintainability, or long-term system health.
• You avoid ownership of outcomes beyond your immediate code changes.
• If reading our Culture Document leaves you feeling neutral rather than energised, hx may not be the place where you’ll do your best work. We’re building something that asks for commitment and conviction, and we want you to feel excited by the opportunity to grow with us.

Compensation

At hx, we’re committed to salary transparency. You’ll always have clarity on pay early in the process - our Talent Partner will share details with you during initial conversations - and we’re working towards publishing salary information for all roles globally.

Because we’re building at the intersection of technology/SaaS and insurance, our roles don’t always map neatly onto traditional benchmarks. Our approach is to design compensation that’s competitive in the market, fair across teams, and aligned with the impact our people make.

Equity: We offer equity across all roles at hx, making it a significant component of total compensation. Your talent partner will be able to share more details about this.

Benefits

• £5,000 training and conference budget for individual and group development.
• 25 days of holiday plus 8 bank holidays (33 days total).
• Company pension scheme via Penfold.
• Mental health support and therapy via Spectrum.life.
• Individual wellbeing allowance via Juno.
• Private healthcare insurance through AXA.
• Income protection and Life Insurance.
• Cycle to Work Scheme

Additional perks

• Top-spec equipment (laptop, screens, adjustable desks, etc.).
• Regular remote and in-person hackathons, lunch and learns, socials, and game nights.
• Team breakfasts and lunches, snacks, drinks fridge, and a fun office at The Ministry.
• Exceptional opportunities for personal development and growth as we build something remarkable together.

Interview process

• Initial call with Talent team (30 minutes)
• Manager Interview (60 minutes)
• Technical Assessment (e.g., code review, system design) (120 minutes)
• Values Interview with Tech Leadership (60 minutes)
• Offer

Our commitment to Diversity

hxer's are at the centre of everything we build. We know that progress depends on diverse perspectives, and we are committed to creating an environment where everyone can thrive, grow, and make an impact. We recognise there is always more to do, and we take responsibility for shaping a workplace that is not only diverse but genuinely inclusive.

Diversity is not just the right thing to do, it is key to solving the complex challenges we choose to take on. By welcoming people from all backgrounds and experiences, we strengthen our ability to question assumptions, push boundaries, and design solutions that endure.

If you’re energised by complexity and motivated to grow, we encourage you to apply and join our global team.

Next steps

If this opportunity resonates with you, we encourage you to apply or share it with your connections! Our dedicated talent team reviews all applications, and we promise to provide feedback regardless of the outcome.

For more information about applying and to view other opportunities, you can visit our careers page.

Please note that background checks will be conducted as part of the hiring process to ensure compliance with our governance policies. We handle all background checks sensitively and in full compliance with relevant regulations. All applicant data will be processed in accordance with data protection regulations and our privacy policy.