Lucis is building Europe’s first preventive health platform: from blood testing to advanced AI-driven insights and action plan.

We already serve 1000+ of users in 🇫🇷, 🇵🇹 and 🇬🇧 and are integrating with dozens of lab partners.

• Team of passionate and tier-1 operators
• Backed by YC X25 and a seed round led by tier-1 investors, athletes & operators
• A live AI "doctor" agent already shipping actionable protocols every day

We’re a small, ambitious team of repeat founders, biohackers.

We’re growing extremely fast (10% week over week) and scaling to empower more Europeans to take control of their health.

Paris-based and YC-backed (X25), we’re funded by a top-tier global VC, a specialised healthcare fund, athletes, and serial entrepreneurs, including the founders of Airbyte, Strapi, Sqreen, WePay, Plato, Veepee, and Zenly.

The role

We’re looking for a full stack software engineer, product-minded, with entrepreneurial DNA and early stage 0→1 experience. It’s a plus if you are passionate about digital health and longevity.

You’ll join as a founding engineer and shape a product that could add healthy years to millions of lives. As the first full-time founding engineer, you will:

• Own mission-critical code from day 1, not tickets
• Shape product and tech choices that will impact thousand of users, starting with yourself
• Solve real-world health data, privacy, and UX puzzles at European scale
• Have a unique opportunity to shape the vision and direction of the company

Our culture

We are building fast, for the long term.

1. Rigor without ego: audits, science, and code deserve the same high bar.
2. Default to action: small PRs, short feedback loops.
3. Radical ownership: you break it, you fix it (and write the doc).
4. Play long games: we’re building a 100-year company to help people live 100 healthy years.

What we offer

• Equity that matters: real ownership at the inflection point. With top-tier salaries.
• Budget for personal care, personal development, and health stipends (we pay your own Lucis tests).
• Quarterly in-person retreats in Europe. We repeat the YC experience every 3 months.
• Hardware of your choice, modern dev-tool stack.
• The chance to directly improve thousands of lives, starting with your own, through smarter preventive care. We are the average of the person we spend our time with.

What you will do

Core responsibilities

• Design and build full-stack features (TypeScript/Next.js, NestJS, Postgres, Prisma).
• Own cloud infra (AWS) and CI/CD (GitHub Actions, AWS CDK) with a security-first mindset. Security is core of what we do (HDS compliant).
• Collaborate with medical advisors, the AI (Founding AI & data engineer), product and design team (‣) to translate biomarker science into reproducible algorithm.
• Architect highly available and scalable systems, with expertise in PostgreSQL performance optimization. Contribute to the scabalibility of our tech stack. Design and maintain improved version of our stack**, implement caching,**
• Maintain strict compliance with HDS and GDPR regulations through robust security measures.
• Drive engineering rituals. Drive continuous improvement through Agile development practices and cross-team collaboration.

Our tech stack

• Typescript mono repo
• PNPM workspaces
• ES linting
• Storybook
• React, NestJS (Node)
• AWS, Fargate, Infra as code AWS CDK
• Docker
• Prisma, Postgres db
• CI/CD Github Actions
• Tailwind

You’ll thrive here if you

• Have 7+ years building production SaaS or B2C apps, including at least one 0→1 journey.
• Can move vertically: front-end → API → data model → DevOps, shipping quality code in each layer. You have 2 core expertises.
• You have experience building systems enabled by AI tools. You are fluent in Cursor PRD files.
• Entrepreneurial, low-ego mindset. You want to build a massive company with massive impact.
• Cautious about your health, actively doing sport. Care about health: you read PubMed abstracts for fun, or track your own biomarkers and metrics.
• Fluent in English. French is a bonus.
• You have led a team before. You remain hands-on more than 80% of your time in your current job.

We’re building the AI health companion people have been dreaming of — always in your pocket, clinically reliable, and deeply personalized.

To get there, we combine:

•	Clinical-grade diagnostics – Blood, microbiome, and lifestyle data integrated from leading lab networks across Europe
•	Biological & medical intelligence – Evidence-based biomarker interpretation powered by the latest in preventive medicine and longevity science
•	AI-native architecture – LLM- and agent-based systems to deliver instant, context-aware health guidance
•	Privacy-first infrastructure – GDPR/health-data compliant, secure-by-design, and interoperable with healthcare standards

Our stack:

•	Frontend: React Native / Next.js
•	Backend: Node.js, Python, PostgreSQL
•	AI & Data: LangChain, OpenAI, vector databases, event-driven pipelines
•	Infrastructure: AWS, Kubernetes, Terraform, CI/CD automation