Do you love shipping products, taking ownership of what you build, and creating experiences that customers truly value?

Then join us as our new Fullstack Engineer and help build the products that enable organisations to find and fix their security weaknesses before attackers can exploit them!

Who are we?

What if cybersecurity could think like a hacker?

At Hadrian, that's exactly what we're building: the future of offensive cybersecurity, powered by autonomous AI agents that think like hackers. Founded in Amsterdam in 2021, we're on a mission to change the way organisations defend themselves by helping them find and fix security weaknesses before attackers can exploit them.

Our platform brings together two products: Atlas, which continuously maps an organisation's external attack surface and validates which exposures are genuinely exploitable, and Nova, which uses AI agents to perform in-depth penetration testing on demand. Together, they give security teams the visibility and proof they need to focus on what really matters and stay ahead of emerging threats.

Backed by $65M in total funding, including our recent $40M Series B led by Forgepoint Capital International and SmartFin, we're investing in the next generation of autonomous offensive security and expanding our impact across global markets. With a team spanning 25+ countries and offices in Amsterdam, London, and New York, we're helping organisations rethink what's possible in cybersecurity.

Join us and help shape the future of offensive security.

Your Role:

As a Fullstack Engineer in our Apps & API team here at Hadrian, you'll play an important role in building and evolving the products our customers rely on every day: Atlas, our continuous scanning platform, and Nova, our agentic pentest product.

In this role, you will get to work across our .NET backend and Next.js frontend, with most of your focus on backend development. From designing APIs and building new features to improving performance and delivering customer-facing improvements, you'll have the opportunity to make a direct impact on our products and the people who use them.

We're looking for an engineer who loves to ship, take ownership, and move fast without compromising on quality. At Hadrian, you won't simply receive a detailed specification and implement it. You'll be given a problem to solve, the freedom to figure out the best approach, and the responsibility to see it through to production. We embrace AI-powered engineering, using agents throughout our development workflows to accelerate delivery while keeping engineering judgement and quality firmly in our hands.

Above all, we're looking for someone who is obsessed with the customer. Someone who cares about the value a feature brings, challenges the way things are done, and proactively looks for opportunities to make our products better.

If you enjoy working in a fast-moving environment where you can make decisions, take initiative, and see the impact of your work, we'd love to hear from you!

What you will do as a Fullstack Engineer at Hadrian:

Build and ship features end to end across our .NET backend and Next.js frontend, contributing to both Nova and Atlas and occasionally supporting other teams' codebases in Python or Go.
Take ownership of projects from technical design to production rollout, making independent decisions and ensuring the solutions you build are reliable, scalable, and maintainable.
Embrace AI-powered engineering by using agents throughout the development lifecycle, from investigating problems and building solutions to reviewing code. You'll evaluate their output, improve their context and instructions, and ensure the quality of what gets shipped.
Work with trunk-based development and document important technical decisions through Architecture Decision Records (ADRs), helping the wider team understand and follow your reasoning.
Own what you build in production, including monitoring, alerts, API performance, and incident management.
Work with large datasets in PostgreSQL, optimising queries and using monitoring tools such as pganalyze to maintain performance.
Collaborate with engineers and colleagues across the company through code reviews, sharing knowledge, and continuously improving our engineering workflows and agentic processes.
Take initiative in improving our products and workflows. If you spot an opportunity to make something better, you'll have the freedom to explore it, build it, and share your solution with the team.
Participate in the team's support rotation and, over time, join out-of-hours support for critical incidents only.
Take on a unique challenge: build specialised products that customers depend on for their critical cybersecurity workflows, while helping shape how AI agents transform the way we engineer software.

You are fit for this job because you:

Love to ship and enjoy moving quickly without compromising on code quality. You're comfortable making independent decisions about technical implementation and user experience, knowing that learning and adjusting along the way are part of the process.
Take ownership of your work, from the initial idea through to production, and are happy to be the go-to person for the features and solutions you build.
Are customer-obsessed and genuinely care about the impact your work has on customers, rather than simply completing tasks or closing tickets.
Have 3+ years of experience building APIs using an enterprise web framework, with hands-on experience in .NET / C#.
Have frontend development experience with a reactive framework, preferably React, and TypeScript. You also have a good eye for design and UX and can turn low-fidelity wireframes into functional, user-friendly features.
Have a solid understanding of SQL databases and ORMs, as well as fundamental system design concepts such as caching, deployments, and how changes can impact the wider system.
Use AI tools and agents extensively but pragmatically. You know how to get the most out of them, while being able to critically evaluate their output and maintain ownership of the technical decisions.
Stay curious about new technologies and trends in the engineering community and enjoy bringing new ideas and learnings back to the team.
Communicate clearly and collaborate effectively with both technical and non-technical colleagues.

Bonus points if you have:

Experience building AI agents or agentic engineering workflows, such as automated code reviews, bug investigation, or bug fixing.
Hands-on experience with Next.js and Tailwind CSS.
Experience working with Python or Go.
Experience optimising queries and working with large PostgreSQL datasets.
Familiarity with Kubernetes and deployment processes.
Experience with event-driven or domain-driven design.
A track record of leading projects from technical design to completion and working directly with stakeholders.
Previous experience in a start-up or scale-up environment, ideally within a fast-paced SaaS product company.
An interest or background in cybersecurity.

Our stack:

C# / .NET (moving to FastEndpoints)
Next.js / React / TypeScript / Tailwind
PostgreSQL / pganalyze
Python / Go (across other teams' codebases)
Kubernetes

Benefits at Hadrian:

Permanent contract
Unlimited paid holiday
Stock options package
Mobile phone stipend
Work-from-home budget
Business travel card
Swapfiets
Referral bonuses

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 100 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? Apply now!

Our clients 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.

Fullstack Engineer