Senior Software Engineer (JVM/Kotlin) - Warsaw

<h1><strong>About hyperexponential (hx)</strong></h1><p>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.</p><p></p><p>Until now, insurance has been making billion-dollar decisions using outdated tools.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.</p><p></p><p>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.</p><p></p><p>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.</p><p></p><p>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.</p><p></p><p>If that sounds like you, join us in building what comes next.</p><p></p><h1><strong>About the Policies team</strong></h1><p>Engineering at hx drives every breakthrough that transforms how insurers make billion-dollar decisions. At the core of our product sits the <strong>Policies</strong> team - the engineers who build and maintain the critical systems that track models, policies, and the complex business logic that powers hx Renew. This team manages some of our most business-critical data and workflows, ensuring that billions in premiums flow through robust, reliable systems.</p><p></p><p>As a <strong>Senior Backend Engineer</strong> in the Policies team, you'll lead the architectural transformation of our core domain while delivering the new features that expand our product capabilities. You'll be architecting the evolution from monolith to modular systems, implementing Domain-Driven Design and hexagonal architecture patterns that will shape how we scale for the next phase of growth.</p><p></p><p>This role combines deep technical leadership with direct product impact - you'll influence architectural decisions that affect the entire platform while building the features that serve nearly 50 of the world's largest insurers. If you want to shape critical systems architecture while seeing your work power billion-dollar insurance decisions, this is where you'll lead that transformation.</p><p></p><h1><strong>What you'll be doing</strong></h1><ul><li><p>Lead architectural modernisation of core business systems, driving the transition from monolith to modular architecture using Domain-Driven Design principles that enable faster development and better system maintainability.</p></li><li><p>Design and deliver complex business logic in Kotlin, Spring, and Hibernate, building robust systems that handle intricate insurance domain models and maintain data integrity for billions in premiums.</p></li><li><p>Shape technical strategy and standards across the team and broader engineering organisation, driving decisions around system design, code quality, and architectural patterns that other teams will follow.</p></li><li><p>Collaborate with product stakeholders to translate complex business requirements into elegant technical solutions, working directly with product managers, designers, and sometimes customers to ensure we're solving the right problems.</p></li><li><p>Mentor and influence engineering culture by establishing coding standards, leading technical discussions, and helping other engineers grow their architectural thinking and technical skills.</p></li><li><p>Drive operational excellence through participation in on-call rotations and building systems that maintain high availability for our mission-critical platform used by enterprise customers worldwide.</p></li></ul><p></p><h1><strong>What you'll need to have done</strong></h1><ul><li><p>Architected and delivered complex backend systems with proven experience leading technical initiatives in Kotlin or other JVM languages, ideally with hands-on knowledge of Spring, Hibernate, or similar enterprise frameworks.</p><ul><li><p>You will be upskilled in Kotlin if you didn’t already use it!</p></li></ul></li><li><p>Led architectural transformation projects with demonstrable success modernising legacy systems, impleme