Fullstack 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.

Role Description

NestAI builds the software and intelligence layer for autonomous defense systems, deployed in live operational environments where reliability isn't a nice-to-have — it's the whole point. As a Full Stack Engineer, you'll own the technical delivery and integration of that platform for our most critical partners.

This is not a traditional implementation or support role. It's a high-stakes, high-ownership full-stack engineering position: you'll build, adapt, and scale modern web applications, decision-support interfaces, and backend integration layers directly against complex customer environments — with the freedom to choose the right tool for the problem rather than inherit a decade of someone else's legacy decisions. We need a versatile engineer who can jump into unfamiliar codebases, connect disparate software ecosystems, and deliver intuitive, high-performance user experiences where software meets the mission.

Day-to-Day Responsibilities:

• Mission-specific full stack engineering: Take technical ownership of building, customizing, and deploying client-facing web applications, operational dashboards, and backend services.

• API & system integration: Design, develop, and deploy robust APIs and backend services that connect NestOS cloud and edge modules with external situational awareness and command systems.

• Frontend execution: Build responsive, high-performance decision-support UI designed for low-latency, mission-critical operational environments.

• Engineering craft under pressure: Hold a high bar for code quality, testing, and observability even while moving fast on-site.

• AI-driven workflows: Use modern AI-assisted development tools to accelerate velocity and rapidly prototype client-requested features without sacrificing platform security or reliability.

• Collaborative problem solving: Work directly with customer technical teams and internal product R&D to translate operational user needs into scalable full-stack features, feeding field feedback back into our core product roadmap.

Qualifications:

• Solid experience (equivalent to 5+ years) as a Full Stack Software Engineer, with a proven track record of shipping complex web applications and backend systems.

• Strong proficiency across the full web stack, including modern frontend frameworks (React, TypeScript) and server-side ecosystems (Node.js, Python, or Go).

• Practical experience building and consuming RESTful APIs and WebSockets, database management (SQL/NoSQL), and hands-on familiarity with Docker, Kubernetes, and deployment pipelines across cloud or on-prem environments.

• A quick study who adapts rapidly to new technical environments, diverse codebases, and shifting customer priorities — you thrive on changing scenery rather than needing a settled, well-trodden stack.

• Strong interpersonal skills, with the confidence to interface directly with external partners, understand user workflows, and translate complex operational needs into software realities.

• Ability to travel occasionally (around 10-25% of your time) to client sites within Stockholm and in Europe.

Preferred, not required:

• Experience in client-facing technical delivery or technical consulting.

• Prior exposure to mapping/GIS libraries (e.g., Mapbox, Cesium) or data visualization.

• Experience in defence or aerospace environments.

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.