Software Engineer (Rust)

About Hyperexponential

Hyperexponential (hx) is creating an AI-driven platform that supports high-impact decision-making in the insurance sector, a market worth about $7 trillion. The product helps insurers decide which risks to accept and how to price them, improving speed, accuracy, and confidence in underwriting and pricing decisions.

The company is transforming insurance from older, manual approaches to a modern system that combines data, AI, and human expertise. Its platform is used by nearly 50 of the world’s largest insurers, has recorded zero churn, and processes billions in premiums.

What started as one product in a single market has grown into a multi-product platform spanning several territories. AI plays a central role, including the creation of a domain-specific AI peer programmer for insurance and new agentic workflows designed to reshape how the industry works.

hx values deep ownership, strong standards, and meaningful impact over hierarchy or tenure. Team members are expected to take on hard problems, work with high discipline, and contribute to a company built for long-term durability.

About the Kernel Team

The Kernel team is responsible for the execution engine at the heart of hx’s platform. This system powers how customer models are evaluated, validated, and executed safely at scale, supporting products such as hx Renew and future offerings.

The team works on advanced technical challenges involving execution, concurrency, memory management, and observability. The goal is to build a reliable and modular engine that can evolve without sacrificing correctness or performance.

In this role, you will take ownership of important parts of the core system from end to end, writing production code, improving design, and working closely with neighbouring teams to ensure the platform meets product and customer needs.

What You’ll Do

• Develop backend capabilities for the Kernel execution engine that strengthen correctness, speed, and reliability for large-scale customer model runs.
• Improve the Kernel’s architecture so it stays clean, modular, understandable, testable, and safe to extend over time.
• Create automated tests and observability tooling for complex execution flows so issues can be found, understood, and resolved faster in production.
• Work with adjacent engineering groups to define Kernel behaviour and interfaces, giving clear technical direction and carrying work through to delivery.
• Take features from design through release, monitoring, and follow-up iterations while balancing immediate needs with long-term maintainability.
• Show hx values by spotting risks early, collaborating constructively, and taking full responsibility in a business-critical platform area.

What You Need

• Experience building and shipping backend systems in a polyglot production environment, using languages such as Rust, Python, or C/C++ and selecting the right tool for each problem.
• Either hands-on production experience with Rust, or strong systems programming experience in C/C++ or Python together with a proven ability to learn new languages quickly; applicants without production Rust experience will be supported through upskilling, though the interview process includes a Rust coding exercise.
• A track record of delivering backend work where correctness, performance, and efficient use of resources were essential, and of improving systems based on real production usage.
• Practical systems thinking across execution, concurrency, and memory or resource management in real backend services.
• Experience building testing and observability that makes complicated backend behaviour easier to understand, diagnose, and safely evolve.
• Evidence of end-to-end ownership, from design and rollout to monitoring and iterative improvement, with early escalation of risks and close collaboration with peers.

What Makes This Role Unsuitable

• This is unlikely to suit someone who prefers very predictable work and is uncomfortable in ambiguous, fast-changing problem spaces.
• It may not fit candidates who prioritise speed over correctness, maintainability, or the long-term health of a system.
• It is not ideal for people who avoid accountability for outcomes beyond their own code changes.
• If hx’s culture document feels merely acceptable rather than energising, the environment may not be the right match for your best work.

Compensation

hx is transparent about pay and shares salary details early in the process through a Talent Partner. The company is also moving toward publishing compensation information for all roles globally.

Because the business sits between SaaS technology and insurance, compensation is designed to be market-competitive, fair across teams, and aligned with the impact each person creates.

Equity is offered in all roles and is an important part of total compensation. More information is available from the talent team.

Benefits

• £5,000 annual budget for training, conferences, and development for individuals and teams.
• 25 days of holiday plus 8 bank holidays, giving 33 days in total.
• Company pension plan through Penfold.
• Mental health support and therapy access via Spectrum.life.
• Personal wellbeing allowance through Juno.
• Private medical cover via AXA.
• Income protection and life insurance.
• Cycle to Work Scheme.

Additional Perks

• High-quality equipment such as a laptop, monitors, and adjustable desks.
• Regular remote and in-person hackathons, lunch-and-learns, social events, and game nights.
• Team breakfasts and lunches, snacks, drinks, and a lively office at The Ministry.
• Strong opportunities for personal development and growth while contributing to a high-impact company.

Interview Process

• 30-minute introductory call with the Talent team.
• 60-minute interview with the hiring manager.
• 120-minute technical assessment, such as code review or system design.
• 60-minute values interview with technology leadership.
• Offer stage.

Diversity and Inclusion

hx says its people are central to everything it builds. The company believes progress depends on diverse viewpoints and is committed to creating a workplace where people can thrive, grow, and make an impact.

It acknowledges that there is still more work to do and takes responsibility for building an environment that is not only diverse, but genuinely inclusive.

By bringing together people with different backgrounds and experiences, hx aims to improve its ability to challenge assumptions, push boundaries, and create lasting solutions.

Next Steps and Background Checks

Interested candidates are encouraged to apply or share the opportunity with their network. The talent team reviews every application and intends to provide feedback regardless of outcome.

Background checks are part of the hiring process to meet governance requirements. These checks are handled carefully and in line with applicable regulations. Applicant information is processed according to data protection rules and the company privacy policy.