Software Engineer - AI Systems
Builds LLM-powered offensive security systems, designing prompt flows, orchestration layers and evaluation frameworks in TypeScript. Offers competitive salary, generous equity and full remote work.
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87,000+ live jobsRemote, Europe (Remote) +5·Full-time·Added 4 days ago (last checked 9 Oct)
US$100,000 - US$350,000 a year
Gross, as stated in the ad.
Full-time
Per the ad.
Fully remote
Per the ad.
The ad doesn’t mention sponsorship
No sponsorship mentioned, and this kind of work is rarely sponsored in Spain.
May fit the digital nomad visa
A remote job for a company outside Spain: you apply yourself, no sponsor needed. It asks for about €2,849 a month in remote income.
Work in English
English is required, per the ad.
Nice to have
Experience building and operating full-stack systems
Proficiency with TypeScript
Experience designing and consuming APIs (REST or GraphQL)
Strong backend development experience (Node.js, Kotlin, Go, or similar languages)
Strong problem-solving skills and the ability to work with incomplete information
A thoughtful communicator who values clarity and simplicity
Comfort working in a fast-paced, early-stage startup environment
Experience with event-driven architectures, message queues, or async workflows
Experience building scrappy, iterative frontends where speed and feedback loops matter more than polish
Familiarity with AWS or similar cloud platforms
Comfort working with infrastructure as code (e.g., Terraform or CDK)
A strong appreciation for user experience and design, even if you're not a formal designer - you care about how features feel as much as how they work
Comfortable prototyping quickly in React/TypeScript and turning ideas into working features fast
Experience designing and optimizing relational databases (we use Postgres), and you know how to structure data for both performance and clarity.
Background in systems programming, networking, or performance tuning
Experience with hybrid deployments (cloud + on-prem) and know how to build resilient systems that handle the complexity of mixed environments.
Experience working in an early stage startup
Prior experience building security products or products for technical users
Compensation & Equity: Competitive salary and a generous equity package, making you a true owner of the company.
Career Growth: Shape your role, lead the function, and grow with the company as we redefine cybersecurity.
Meaningful Work: You will tackle technically complex challenges and play a pivotal role in the growth of our business, working alongside an amazing team and some of the world's experts to shape how AI transforms cybersecurity.
We're looking for a Software Engineer who's passionate about building reliable and high quality products with robust backend systems. In this role, you'll design and implement end-to-end features across the stack: from React-based frontends and TypeScript APIs to backend services in Kotlin and Go, all deployed on AWS.
You'll be joining a small team of superstars that's shipping quickly and operating with high trust. This is a role for someone who loves to own open-ended problems and figure things out-whether that's designing seamless API contracts, optimizing database interactions, or building scalable systems that make powerful AI capabilities accessible. If you like being at the intersection of deep tech and real-world impact, you'll feel right at home.
Design and build full-stack systems that integrate frontend and backend seamlessly
Develop scalable APIs and backend services in TypeScript, Kotlin, and Go
Deploy and operate services in AWS and other cloud providers
Own problems end-to-end-from design through deployment to production support
Navigate ambiguity and help define how we build as much as what we build
Collaborate closely with teammates across the stack, including AI researchers, Security researchers and backend engineers
XBOW is a cybersecurity company specializing in offensive security testing and AI-driven security solutions. The company develops autonomous penetration testing technology and AI security systems for enterprise clients, operating at the intersection of cybersecurity and artificial intelligence. XBOW is a relatively young, fast-growing company with a global footprint, serving clients across EMEA and beyond.
In Spain, XBOW has established a presence as part of its EMEA expansion, with open roles for software engineers focused on platform/core infrastructure and AI systems. The company's work culture is technical and product-driven, appealing to international engineers interested in cutting-edge security technology. With a distributed team and remote-friendly practices, XBOW offers opportunities for relocating professionals to contribute to a high-growth, VC-backed startup.
Build the future of offensive security with XBOW. Attackers are already using AI to move faster than defenders can react-we're creating the platform that puts security ahead in the arms race. Our AI-powered system autonomously discovers, validates, and even exploits vulnerabilities, giving organizations proof-backed results in hours instead of weeks.
Founded by Oege de Moor, creator of GitHub Copilot, and backed by Sequoia, Altimeter, and other leading investors, XBOW is applying cutting-edge AI to one of the world's most urgent problems. In just over a year, our AI, built by a world-class AI team and legendary security researchers - has uncovered thousands of real-world zero-days across the software billions rely on, and achieved the #1 ranking on HackerOne's global leaderboard.
We're a team of builders, hackers, and researchers who thrive on solving problems others think are impossible. If you want to push the boundaries of AI, reshape how security is done, and join the group defining this new era of defense - we'd love to talk.
Location: Remote (all team members are remote but we meet regularly and you're supported to travel to collaborate with colleagues in person)
Contract: Full-time.
45-min introductory chat with our Talent team.
45 minutes with one of our Engineering Leads.
2-3 hour technical deep dive around relevant case study.
30-min final meeting with the Engineering Lead for the assigned team..
We aren't focused on seniority titles at XBOW-so if you're worried about "leveling," don't be. We care a lot more about mission fit, capability, and impact than what's on your LinkedIn headline.
We believe in people who are driven by curiosity and a willingness to learn. Even if you don't check every box, we encourage you to apply if you're excited about the role and our mission.
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