Does the idea of building AI agents that push the limits of offensive cybersecurity gives you butterflies?

Then look no further, and join us here at Hadrian as a Software Engineer focusing on building AI Hacking Agents!

Who are we:

We are Hadrian - an offensive cybersecurity startup. We are reshaping the future of offensive cybersecurity with AI agents built by hackers. Founded in August 2021, we've secured funding and the backing of ABN AMRO Ventures and Cherry Ventures, propelling us into a new era.

Our goal is to provide companies with an autonomous Threat Exposure Management platform. At Hadrian, we view security through a hacker's eyes because hackers understand hackers best. We continuously map the digital footprint of organisations, discover risks, and prioritise remediation for security teams to harden their external attack surfaces.

Located in Amsterdam's buzzing Leidseplein, by London's famous Paddington Station, and our most recent US HQ in the heart of New York City, our diverse team from 25+ countries is on a mission to shake things up in offensive security. Join us in making waves and securing over 700 businesses, and be at the forefront of automated offensive security.

Your role:

As a Software Engineer on Hadrian's AI team, you will help build and evolve our world-class AI hacker. You'll work on our agentic pentest product, as well as new AI-powered capabilities that push the boundaries of what automated hacking can do.

We’re looking for someone who will take ownership of projects from ideation through development, release, and maintenance, working across everything from agent harnesses, software architecture, prompts and deployments. This is a role for engineers who enjoy getting close to the problem, moving quickly, and turning ideas into production-ready systems without unnecessary process getting in the way.

You'll also be part of the team operating these systems in the real world! Your tasks will include evaluating pentests, investigating issues, and continuously improving the agents based on what you learn.

If you're excited by the idea of combining strong software engineering with cutting-edge AI to build systems that can actually hack, we'd love to hear from you.

What you will do as a Software Engineer working on AI Hacking Agents:

• Build and optimize AI hacking agents that autonomously perform offensive security tasks and power Hadrian's agentic pentest product.

• Own projects end-to-end, from identifying an opportunity and designing a solution to shipping, operating, and iterating on it in production.

• Evaluate and optimize agent performance, using real-world pentest results and feedback to make our AI hackers more capable and reliable.

• Build high-quality, reliable, and debuggable software across LLM applications, agent harnesses, APIs, prompts, and data models.

• Respond to production issues and bugs, helping ensure our AI systems remain reliable as they operate against real-world targets.

• Move quickly from idea to MVP, learn from real-world feedback, and iterate until you have something that works.

You are fit for this job because you:

• Are cracked at Python and have experience owning high-reliability Python codebases.

• Have hands-on experience building with LLM APIs.

• Have 3+ years of software engineering experience or equivalent experience building production software.

• Are comfortable taking end-to-end ownership of ambiguous and high-impact projects, including communicating with stakeholders outside of engineering.

• Are pragmatic and biased toward action. You ship a MVP quickly, learn from feedback, and improve it rather than waiting for perfection.

• Are excited to work 50%+ in person from our Amsterdam office.

Bonus points if you have:

• Built AI agent harnesses or worked with agentic frameworks such as LangGraph, LangChain, or PydanticAI.

• Experience with TypeScript, Go, or C#.

• Experience with Kubernetes, GCP, or AWS.

• Hands-on hacking or offensive security experience.

• Contributed significantly to open-source AI projects or repositories.

• Published research or presented at conferences in AI or related fields, alongside strong practical engineering experience.

• Experience building AI products at a startup or scale-up, or having founded a company yourself.

Benefits at Hadrian:

• Unlimited paid holiday

• Stock options package

• Mobile phone stipend

• Work-from-home budget

• Business travel card

• Swapfiets

Why you want to be part of Hadrian:

Make the internet safer: We enable companies to protect their customers, employees, and other stakeholders from malicious hackers by providing real-time Exposure Management from the Hacker’s perspective

Board a primed rocket ship: Hadrian is growing fast; the team is approaching 90 wonderful people, notable customers are signed, and significant funding is raised. Now is the time to join our high-growth journey

Be part of a strong and dynamic culture: Our values define who we are as a group and serve as the cornerstones to guide us in building a product that our customers love. At Hadrian, we achieve this by championing a culture that takes ownership, succeeds together, increases velocity, and pursues growth

Sounds like the role for you? Hit the apply button!

Our customers are seeking a world-class and reliable digital security service. That is exactly what we are offering. Therefore, a background check will be part of the process.