Fullstack Engineer

NestAi Oy; Stockholms kommun; On-site; SEK 900,000 - 1,200,000; Full time

Job summary

NestAI seeks a senior Full Stack Engineer to own the delivery and integration of its platform for critical defense partners. You will build web apps, dashboards, and backend services, connecting NestOS cloud and edge modules with external systems.

You will work in a high-ownership environment, capable of adapting to unfamiliar codebases, delivering fast without compromising security, and collaborating across customer teams and R&D to ship features that matter in live operations.

Qualifications

• 5+ years of experience as a Full Stack Engineer with delivery of complex web apps.
• Proficiency in React/TypeScript and server-side ecosystems (Node.js, Python, or Go).
• Experience building RESTful APIs and WebSockets; familiarity with Docker and Kubernetes.
• Ability to quickly learn new codebases and work across cloud or on‑prem environments.
• Willingness to travel to customer environments when needed.

Responsibilities

• Own technical delivery and integration of platform for key partners.
• Develop client-facing web apps, dashboards, and backend services.
• Design and deploy robust APIs connecting NestOS cloud and edge modules.
• Build high-performance, low-latency UI for mission-critical ops.
• Collaborate with customer teams and R&D to translate needs into features.

Skills

Full stack experience

React/TypeScript

Adaptability

Interpersonal skills

Willingness to travel

Tools

Docker

Kubernetes

REST APIs

WebSockets

SQL/NoSQL DB

Job description

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. Most of what you encounter here won't have a known answer yet; you'll work it out alongside a small, senior team that has full ownership of the problems in front of it, and a product organization that takes field feedback seriously enough to ship it back into the platform in days, not quarters.

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.

• Willingness to travel to and work in customer environments as needed.

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.

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.

Practicalities

Employment is subject to applicable security screening.

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