About Hyperexponential (hx) At hyperexponential, we're building the AI-powered platform that enables the world's most critical decisions in a $7 trillion industry, which risks to take, and how to price them. These are the decisions that shape real-world outcomes: whether rockets successfully launch into space, autonomous vehicles make it to market, or communities recover after major storms.

Until now, insurance has been making billion-dollar decisions using outdated tools. We're changing that. Our platform brings together data, AI, and human expertise to give insurers the fastest path from submission to decision - helping them move faster, act smarter, and take on more risk with confidence.

Backed by a16z, Highland Europe, and Battery Ventures, we're scaling globally - already trusted by nearly 50 of the world's largest insurers, with zero churn and billions in premiums flowing through hx.

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 Models Team The Models team at hx is at the heart of our mission to empower customers with the tools to write, version, test, and visualise their models, directly impacting the core functionality of our platform. We are responsible for rearchitecting our technology stack to deliver features rapidly and securely, ensuring our services can handle increasingly complex and nested customer data.

Our team blends deep technical skill with a culture of collaboration, ownership, and open communication. We work closely across disciplines, tackling complex data and performance challenges that drive real customer value. Constructive challenge and transparent leadership are central to how we operate, with a focus on delivering reliable, scalable solutions.

As a Senior Backend Engineer, you will play a pivotal role in improving the scalability and reliability of the Models service, accelerating delivery through well-designed abstractions and strong software architecture decisions. You will also be a cultural force, leading by example in ownership, kindness, and proactive problem-solving.

What You’ll Be Doing

• Designing and implementing scalable backend solutions that enable the Models platform to handle increasingly complex and nested customer data, directly improving reliability and performance.
• Addressing technical debt and driving forward-looking architectural changes to support rapid growth and evolving customer needs.
• Building reusable components and abstractions that accelerate delivery across the group and empower other teams to move faster.
• Collaborating with cross-functional teams, including those working in Python, Rust and Kotlin, to deliver features that have measurable impact on customer experience and platform adoption.
• Leading by example in ownership, kindness, and proactive problem-solving, fostering a culture of continuous learning and high performance.
• Contributing to the rearchitecture of our core model code base, aligning with modern industry standards and preparing the platform for future challenges.

What You’ll Need To Have Done

• Architected and delivered complex backend systems with proven experience leading technical initiatives in Python
• Our teams use a combination of Python, Rust and Kotlin. Expect to be upskilled in Rust if you didn't already use it!
• Built and deployed cloud applications at scale, demonstrating the ability to deliver robust solutions in production environments.
• We use AWS with ECS, EC2, Fargate, Lambda
• Designed and managed complex, arbitrary nested data structures tailored to diverse customer requirements.
• Demonstrated strong working knowledge of fundamental computer science and software engineering principles, including algorithms, data structures, complexity, design patterns, and architecture.

You’re unlikely to thrive here if

• You prefer staying in your comfort zone or working only on narrow, well-defined tasks.
• You avoid ambiguity, expect rigid processes, or are not proactive in driving solutions.
• You are uncomfortable with learning new technologies or taking ownership of complex problems that span multiple systems and teams.

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 Depending on how you choose to join hx (B2B or UoP), your benefits can look like:

B2B

• Share Options at a highly successful Series B company
• 25 days of non-working + 14 Polish bank holidays
• £5,000 budget for Learning & Development
• Mental Health Support and Therapy via Spectrum Life
• Optional for you: access to Healthcare package provided by Luxmed + Multisport (fully funded by yourself as B2B Contractor)
• Top-spec laptop (MacOS or Windows)

Contract of employment (UoP)

• Share Options at a highly successful Series B company
• £5,000 budget for learning & development
• 26 days of holiday + 14 Polish bank holidays
• Company pension
• 10 days company sick pay at 100% salary, thereafter in line with labour law
• Mental health support and therapy via Spectrum Life
• Monthly wellbeing allowance via Juno
• Healthcare package provided by Luxmed
• Multisport card at Classic level
• Top-spec work equipment (MacOS / Windows + additional monitors, mechanical keyboards etc)

Interview process

• Initial call with our Talent team (30 minutes).
• Manager Interview (60 minutes).
• Technical Assessment: Bi-Directional Code Review with Systems Design (120 minutes).
• Values Interview with Tech Leadership (60 minutes).
• We offer!

Our commitment to Diversity hxers 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.