Summary: Join a mission-driven team shaping a preventive health platform by designing and building full-stack features, owning critical code, and making product decisions. Highlights: 1. Shape product and tech decisions with real-world impact on health data and UX 2. Build across the full stack with a security-first mindset and compliance focus 3. Work with an entrepreneurial team focused on radical ownership and impact Lucis is building the preventive health platform every European deserves. From advanced blood testing to AI\-driven insights and personalized action plans, we are transforming healthcare by replacing reactive sick\-care with a proactive, member\-first approach. **Where we are today:** * 4,000\+ paying members across France, Portugal, and the UK * Growing 10% week over week * A live Doctor AI agent producing evidence\-based protocols daily * 17 people on the team, across tech We’re Paris\-based, YC\-backed (X25\), and funded by General Catalyst, a top\-tier global VCs, healthcare specialists, and serial entrepreneurs, including the founders of Airbyte, Strapi, Sqreen, WePay, Veepee, and Zenly. **What we are looking for** We're looking for a senior software engineer — product\-minded, with entrepreneurial DNA and 0\-to\-1 experience. You'll shape a product that could add healthy years to millions of lives: * Own mission\-critical code from day 1, not tickets. * Shape product and tech decisions that directly impact thousands of members. * Solve real\-world puzzles in health data, privacy, and UX at European scale. * Build across the full stack, from frontend to infrastructure, with a sharp edge in at least two areas. **What you'll do** * Design and build full\-stack features (TypeScript, Next.js, NestJS, Postgres, Prisma). * Own cloud infrastructure (AWS, CDK) and CI/CD (GitHub Actions) with a security\-first mindset — we're HDS\-compliant. * Collaborate with medical advisors, the AI team, product, and design to translate biomarker science into reliable software. * Architect scalable, highly available systems with strong PostgreSQL performance. * Maintain strict GDPR and HDS compliance through robust security practices. * Drive engineering rituals and continuous improvement. **Our stack** * Platform: TypeScript monorepo, React/Next.js, NestJS, PostgreSQL, Prisma, Tailwind * AI/Data: Python, LangChain/LangGraph, PGVector, GCP/Vertex AI, BigQuery, Airbyte * Infra: AWS, Qovery/Kubernetes, Docker, GitHub Actions * Tools: Linear, Figma, Notion, Slack, Cursor **You'll thrive here if you** * Have 7\+ years building production SaaS or B2C apps, including at least one 0\-to\-1 journey. * Can move vertically: frontend API data model DevOps, shipping quality code at each layer. You have 2 core specialties. * Build and experiment with AI tools daily. You're proud of your definition of engineering in 2026\. * Have an entrepreneurial, low\-ego mindset — you default to action and fix what you break. * Care about health — you track biomarkers, do sport, or read PubMed for fun. * Are fluent in English. French is a plus. * Have led a team before, but remain hands\-on 80%\+ of your time. **Our culture** We move fast and aim high for the long term: * **Rigor without ego**. We hold audits, science, and code to the same high standard. * **Default to action**. Favor small PRs, swift feedback, and daily shipping. Everyone use Claude Code in the team * **Radical ownership**. If you break it, you fix it (and document it). * **Play long games**. We’re building a 100\-year company to help people live 100 healthy years. We are together\-first in Paris, not remote\-first nor strictly 9\-to\-5\. Building a movement means showing up, challenging each other, and growing as a team. **What we offer** * Meaningful equity and competitive salaries * Health stipend, we pay for your Lucis tests (you’re user \#1\) * Quarterly retreats across Europe to recreate the YC experience * Hardware of your choice and a modern dev tool stack * Learning budget for books, courses, and conferences * Flexible schedule, we care about output, not hours logged **Who you will work with** Join a team of repeat operators from Algolia, Instacart, Alan, Doctolib, Padoa, and Gorgias, people who have scaled products to millions and know how to build from zero. You’ll also collaborate with leading physicians, our Chief Medical Officer, and enjoy deep connections through the YC founder and advisor network.