Full-Stack (Sr.) Software Engineer

Who We Are

Every Decade adds a new Security Layer. The next is VISS’s Endpoint Isolation Layer. We are building a ground-shifting hardware platform to secure our digital infrastructure - from the most mission-critical military assets to your own private consumer PC. Why? Because software-based defense mechanisms (VMs, AVs, EDRs, etc.) are inherently flawed: they fight in the same domain they try to defend against. That's why @VISS we are taking the fight from the Software to the Hardware Domain. Our architecture blocks entire classes of attacks by design - with the help of Physics. Our motto is simple: Physics > Code.

To help us strengthen the digital backbone of our civilization, we’re looking for a relentless Engineer to join our mission. Now, let's be brutally honest about what it means to work here.

We are a small team of ±15 obsessives. Every single person at VISS is an outlier - a genuine specialist operating at the top of their field. We don't hire good engineers. We hire the ones other companies build teams around. If you're not regularly told you're unreasonable in your standards, you probably won't fit in here.

This is not a 9-to-5. This is not "work-life balance" culture. This is a startup pioneering what we believe is the most significant leap in cybersecurity since the invention of the internet - and that kind of ambition demands a different breed of commitment. Expect long hours, relentless intensity, and the kind of deep technical challenges that will stretch you far beyond your comfort zone. The pay in this phase reflects early-stage startup reality, not BigTech comfort. You're here because you believe in the mission and because building something that actually matters is worth more to you than a padded salary at a company that ships another SaaS dashboard.

We are not building another app. We are building a new security primitive at the intersection of hardware, physics, and software - and we need people who are genuinely extraordinary to pull it off. If "extraordinary" feels like a stretch when you describe yourself, this role is not for you. No hard feelings.

The Role

Full-Stack (Sr.) Software Engineer. You will own crucial parts of our secure software architecture, working across the stack from close-to-the-metal Linux OS configuration up to backend cloud infrastructure. We need a strong generalist with excellent software exposure who can build secure local apps, harden systems, and connect our devices seamlessly to cloud services. Priorities constantly shift, new projects always pop-up and state-of-the-art solutions need to be developed.

A note on "Full Stack": If your definition of full stack is JavaScript, React, Node.js, and some Python - please do not apply. That is not full stack here. At VISS, full stack means you are equally comfortable writing bare-metal C for a custom PCB, hardening a minimal Linux OS, architecting a secure cloud backend, and debugging kernel-level issues at 2 AM. If that sentence excites you, keep reading. If it intimidates you, we respect that - but this isn't the right fit.

What You’ll Be Doing:

• Secure App Development: Designing and writing robust applications and services that run directly on our edge devices.
• Backend & Cloud Integration: Developing and expanding the VISS Store cloud/server backend, ensuring secure and seamless communication with our hardware.
• OS Hardening & Infrastructure: Configuring the core OS architecture to create minimal, tamper-proof, read-only environments.
• Hardware Interfacing: Writing the software that interacts directly with our custom PCBs.
• Kiosk Interfaces: Building lightweight, highly resilient boot-to-app UI interfaces.

What You Bring:

• Software Engineering Excellence: Deep overall software development exposure. You understand solid architecture, whether you're working on embedded software, APIs, or cloud backends.
• Languages: Strong coding skills in Python, Rust, C, or C++, alongside very solid Shell (Bash) scripting.
• Embedded Linux: Solid understanding of the Linux OS, systemd, and managing headless environments.
• Communication: Fluent English + at least 1 other European language (German is highly preferred).
• Security Clearance Eligibility: Due to the sensitive nature of our work and our involvement with NATO, applicants must be eligible for NATO security clearance (requires citizenship from NATO member country).

Nice to have:

• Experience in building custom Linux images using the Yocto Project or Buildroot.
• Security Clearance Holder & or Military Background

Why Join Us?

Let's not sugarcoat it: this will be one of the hardest things you've ever done professionally. The hours are long, the problems are novel, and nobody is going to hold your hand.

But here's what you get in return:

• You'll be joining a tight, elite team where your work immediately impacts critical security infrastructure used by defense organizations and, eventually, millions of consumers. No red tape, no politics - just exceptional engineering, fast iterations, and a mission that genuinely matters to the security of our civilization.
• This is a 100% on-site role. Our office is located in the iconic Hoepfner Burg in Karlsruhe. You literally get to build cutting-edge cyber defense technology from inside a castle, surrounded by an awesome tech ecosystem.

If you've read this far and you're still excited - we want to hear from you. If you've read this far and you're looking for reasons to talk yourself into it - you probably shouldn't.