Software · Citadel
Senior Software Engineer, Citadel
Build Citadel, the command software that gives operators one picture and keeps a person in command of every use of force.
About Vaubren
Vaubren is a European defence technology company developing aircraft, command software, sensing and electronic warfare as one integrated system, with a person in command of every use of force. Our engineering team is based in Bulgaria, inside the European Union and NATO.
The role
You will build Citadel, the software that brings every sensor and aircraft into one picture and keeps a person in command of every use of force. The hard problems are real-time data from many sources over links that drop, an interface that stays clear when pressure is highest, and a record of every action that operators and commanders can trust. You will work on the interface, the services behind it, or both, and you will see it used in the field.
Why this role
- Citadel is where every Vaubren system meets the operator, so your work shapes how all of our products are used
- You build responsible command and control from the start: a person in command of every use of force, by design
- Early team, real ownership and direct contact with the people who use the software
What you will do
- Own a major part of Citadel end to end, from design through deployment and field feedback
- Build the services that ingest, fuse, store and share tracks and video from sensors and aircraft in real time
- Design for intermittent, low-bandwidth links, with clear behaviour when data is late, missing or conflicting
- Build operator interfaces for maps, tracks and alerts that stay clear under pressure, with an explicit authorisation step for every action
- Design permissions, audit trails and activity logs that make every decision traceable
- Make Citadel simple to deploy on rugged hardware and isolated networks, and secure by default
- Test with operators in realistic exercises and turn what you see into the next release
What you bring
- Typically 6+ years shipping production software in distributed systems, real-time backends or demanding frontends
- Strong skills in a modern language such as TypeScript, Go, Rust or C++
- Experience designing systems that keep working when the network does not
- Care for security, reliability and usability, and the judgement to trade them openly
- A record of owning features from idea to production and supporting them in use
If you meet most of these points but not all, we still encourage you to apply.
Nice to have
- Mapping and geospatial software, such as WebGL map rendering or geospatial databases
- Real-time messaging and streaming systems
- Software for defence, emergency services, air traffic control or other critical users
- Deployment on isolated networks and edge hardware
Working at Vaubren
- A full-time role in Bulgaria, inside the European Union and NATO
- Work across the whole system, from design review to field test
- Small teams with real ownership of their work
- Relocation discussed with each candidate
- Responsibilities, compensation and start date agreed in writing
How we hire
- 01
Application
Apply for a role or send an open application. Every application is reviewed by the team that is hiring.
- 02
First conversation
A call about your experience, the role and what you are looking for.
- 03
Technical interviews
A discussion of your past work and a practical problem drawn from the role.
- 04
Meet the team
Meet the people you would work with, in person in Bulgaria where possible.
- 05
Offer
Responsibilities, compensation and start date, agreed in writing.
Security and eligibility
Some roles involve work that is subject to security vetting and export control. Where a role requires it, we explain the process early, and an offer may depend on eligibility for national security clearance. You do not need a clearance to apply.
Vaubren is an equal opportunities employer. We welcome applications from everyone with the skills for the role, whatever their background. If you need an adjustment during the hiring process, tell us and we will make it.