Simulation Engineer, Multiplayer & Networking If you’re someone who has shipped real multiplayer products and who thinks about long-term architecture as much as day-to-day implementation, then this role might be just right for you! Company NestAI is a European AI lab for defence delivering the adaptive operating system for modern battlefield operations. We develop adaptive intelligence for unmanned and command systems: AI that continuously learns from operational data and adapts to changing conditions. NestOS is our open, modular and interoperable platform that 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 brings together over 200 engineers and scientists and partners with leading European defence forces and industry. Role Description You'll join NestAI's Simulation Chapter, the team building the simulation platform that lets us test and validate autonomy software long before it touches real hardware. This role is about making that simulation multiplayer: letting multiple simulated agents work together in a shared world, at scale. If you’re someone who has shipped real multiplayer products and who thinks about long-term architecture as much as day-to-day implementation, then this role might be just right for you! Day-to-Day Responsibilities: Design and build the multiplayer and networking architecture that lets multiple simulated agents operate together in a shared environment. Keep simulated systems synchronised in real time as they scale across more machines and more agents. Own how data moves out of the simulation and into the systems that depend on it. Help the simulation platform scale in the cloud rather than staying limited to a single machine. Work closely with the rest of the Simulation chapter and other engineering teams to keep the multiplayer environment realistic and useful. Help shape where the platform goes next as our simulation needs grow more complex. Qualifications: Deep experience building multiplayer and networked systems in a modern real-time engine (e.g., Unreal Engine 5). A track record of shipping real, live products, not only prototypes or client projects, with the mindset of someone who owns long-term outcomes. Experience with real-time video or data streaming. Strong communication skills. You'll work with many other teams, so being able to figure out what a team actually needs matters. A mindset built for scale: you've worked in larger engineering teams or organisations, not only as a solo or small-team contributor. Experience deploying real-time or simulation workloads to the cloud is a plus 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. Department Simulation Locations Helsinki, Tampere, Turku Remote status Hybrid Employment type Full-time About NestAI Physical AI is moving from theory to reality. The systems being built today will shape how societies protect people, operate critical infrastructure, and respond under pressure for decades to come. At NestAI, close to 200 engineers and scientists work at the intersection of software, hardware, and AI — developing autonomy, sensing, and command capabilities for mission-critical use. This isn’t demo work. It’s real systems, built for real environments. We build in Europe, with open and interoperable architectures, so that critical capabilities can evolve over time without lock-in — and remain accountable to the societies they serve.