Founding Principal Engineer (m/f/d) // Ferto AI

About us Most labs still count cells under a microscope by hand. It's slow, repetitive, and error-prone. We're replacing that manual work with software. By combining a standard microscope with a smartphone, we run computer vision models that locate, track, and measure cells automatically in real time.

We're starting with semen analysis and expanding to other routine microscopic samples. Based in Berlin, we're a small, well-funded team founded in 2026 operating in stealth. Our goal is to make automated, reliable diagnostic analysis accessible on any phone connected to a microscope.

The role We're looking for an engineer who wants to own the whole platform behind a medical product: services, data, infrastructure, security and identity. A first version runs today.

The hard part is making it trustworthy enough for clinical use: patient data that stays safe, an audit trail that holds up for years, and a system that recovers when something breaks. You'll own all of it, working closely with the founders and our CTO.

What you'll do Own the platform end to end: backend, data, infrastructure and security. Get it ready for clinical use, and keep it reliable as we grow. Build identity, access and data handling that clinics and auditors can trust. Make the architecture calls: what to build now, what to defer, what to cut.

Set the engineering standard and help hire the team that follows. What you bring Platforms you've built and run. You've built backend platforms from scratch and run them in production, through outages, data incidents, migrations and growth. Database depth.

You know what happens under the query: indexing, locking, transactions, replication, zero-downtime schema changes, and backups you've actually restored. Security by default. Authentication and authorisation, tenant isolation, secrets, audit logging. You think about how a system gets attacked before it ships.

Identity done properly. Identity providers, sessions and tokens, roles and permissions, onboarding and