Principal Software Engineer – Cyber Security Research - On Site Barcelona - Zero to One Build
I'm looking for a Principal Software Engineer to join a next generation Cyber Security Research start up based in Barcelona (You do not need Cyber Security experience to apply) , who are building mission critical systems that protect national security interests across Europe. Given the importance of this position, we need someone who can be on site 5 days a week in Barcelona.
You’ll be solving hard problems around distributed execution, workflow durability, secure orchestration, disconnected environments, and large scale system resilience, sitting at the intersection of cybersecurity and government technology. It’s designed for self hosted and hybrid environments where data sovereignty, privacy, and uncompromising security are non negotiables. They're not building another SaaS tool, they're building resilient, sophisticated infrastructure that matters.
The Opportunity




They're looking for a Principal Software Engineer to be the first engineering hire on this project and technical founder of this new division. You won’t be implementing someone else’s spec, you’ll co design the product and architecture directly with the founders, write production code from day one, and lay the foundation for everything that follows.
This is a true zero-to-one role: architect, coder, system designer, and future team builder rolled into one.
What You’ll Do
- Partner with founders to translate a bold product vision into a world class technical architecture and initial codebase.
- Design and build complex, high throughput distributed systems optimised for hybrid, air gapped, and on prem deployments.
- Own the core workflow automation/orchestration engine , including deep understanding of its inner workings, customisation, and extensibility.
- Build AI ready data pipelines and architecture so we can integrate advanced capabilities without rewriting core systems later.
- Establish production grade K

📌 Principal Software Engineer (España)
🏢 CBSbutler
📍 España