Senior Full Stack Engineer

Company

NestAI builds the adaptive operating system for modern battlefield operations. Most AI systems are built once, validated at deployment, and expected to stay sufficient after that. That assumption holds until conditions change, and in defence, they always do. Our team develops adaptive intelligence for unmanned and command systems: AI that continuously learns from operational data and adapts to changing conditions, deployed in environments where there is no internet, no GPS, and failure is not an option. NestOS, our open, modular, and interoperable platform, enables this at scale and keeps capability evolution under sovereign European control.

Founded in 2025 by Peter Sarlin, whose previous company Silo AI became Europe's largest AI acquisition, NestAI has grown to over 200 engineers and scientists and partners with leading European defence forces and industry. We're ambitious about what we're building and honest with each other. The bar is high, and so are the standards we hold ourselves to. But this is also a place built on humility, trust, and looking after each other. If that sounds like the kind of work you want to do, keep reading.

Join us as a Senior Full Stack Engineer

We are looking for an experienced Senior Fullstack Developer to join our team. This is a role for a strong TypeScript and React engineer who has a solid mental model of how React renders and why, and who thinks carefully about the APIs other developers depend on. You will help build the operator-facing software at the center of our platform—interfaces that decision-makers rely on in environments where failure isn't an abstract concern.

As a Senior Fullstack Developer, you will work at the intersection of micro-frontend architecture, shared packages other teams build on, and high-volume real-time visualization on web-based maps. You will collaborate closely with Forward Deployed Engineers who bring field feedback back into the product, bridging real-world operational constraints directly with core platform architecture.

What you’ll work on

- Operator-facing applications built from independently deployed micro-frontends
- Shared packages that other teams build on.
- High-volume, real-time visualization on web-based maps.
- Close collaboration with Forward Deployed Engineers, who take our software into partner environments and bring field feedback back to the product.

What We're looking for

- 5+ years of professional software engineering, most of it on production web applications in TypeScript and React.
- A solid model of how React renders and why. Hands-on experience with React 19 and its concurrent features (actions, transitions, the compiler) is a plus. If you haven’t used them in production yet, we’ll help you catch up.
- An eye for detail in layout, typography, motion and keyboard interaction behaviour.
- Experience designing and maintaining APIs that other developers depend on. You think about the person calling your code and what happens to them when you change it.
- Fluency with modern CSS, the browser platform, build tooling and monorepos.

Nice to have

- Production experience with micro-frontend architectures, including host and remote contracts, shared runtimes, and independent releases
- Hands-on work with geospatial rendering, mapping libraries like MapLibre, deck.gl , or Cesium, or GPU-accelerated visualizations
- Handling real-time, high-frequency browser data using streaming, binary formats, and Web Workers
- Open-source library maintenance for active user bases or design system development
- Experience in defense, aerospace, or other high-consequence domains where software reliability is critical

If your background doesn't match every requirement but the work resonates with you, we'd encourage you to apply. How you think, learn, and take ownership matters more to us than ticking every box.

Why join NestAI

At NestAI, you’ll build meaningful, real-world technology as part of a world-class team of engineers, scientists, and experienced professionals. You’ll work on systems where reliability genuinely matters, contribute to Europe’s security and resilience, and solve problems that demand depth, trust, and craftsmanship.

If you want to build with purpose - and with leading experts in the field - you’ve come to the right place.

What we offer

We offer a growing set of practical benefits to support your work and wellbeing, day to day:

- Occupational healthcare (currently provided by Mehiläinen)
- Epassi Flex benefit (sports, culture, commuting, wellbeing)
- Lunch benefit (25% tax-free coverage)
- Regular team lunches and all-hands events
- Your choice of Mac or PC
- Holiday allowance (50% of holiday salary)
- Phone benefit according to company policy (subscription and device)
- We are continuously developing and expanding our benefits as we grow.

Practicalities

Employment is subject to applicable security screening (including SUPO, where required).

NestAI is an equal opportunity employer. We consider all applicants based on their skills, experience, and potential.