Penetration Tester

You’ll be part of a team that focuses on vulnerability testing, hunting, disclosure processes, and security monitoring. You won’t just run tests, you’ll help raise the bar for security across the organization. As an experienced security tester, you play a critical role in keeping systems safe. You find vulnerabilities before attackers do. You perform penetration tests, review code, and work closely with development teams to help them fix issues and build more secure software.

We’re not just looking for someone who can break things. We want someone who knows why they break, how to fix them, and how to make sure they stay secure. If you love thinking like an attacker but collaborating like a teammate, read on!

— Willem Heutink

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Penetration Tester

40 hours

Senior

September 1, 2025

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What will you be doing?

Perform security tests and penetration testing on web and mobile applications
Review source code (.NET, Java, React, AngularJS) for security flaws
Test mobile apps (iOS, Android)
Use DAST, SAST, and code scanning tools
Assess infrastructure (Azure, AWS, Linux, Windows)
Report vulnerabilities clearly and advise on fixes
Collaborate with dev teams in an Agile environment

Who are you?

You are someone who doesn’t just work with precision, you think ahead. You know that security is more than just testing for vulnerabilities; it’s about trust, responsibility, and protecting real people behind the systems. That’s why you make sure everything is airtight, down to the smallest detail. At the same time, you care about your own growth. You’re not just looking for your next assignment , you’re looking for a place where you can learn, make impact, and do work that truly matters.

Develop yourself with Live your potential

We believe that personal growth and balance are key to continued success. That's why at Kayak, you get access to Live your potential: our personal development program that helps you grow not only as a professional, but also as a person.

Together with your Field Manager and professional coaches, you will work on themes such as resilience, leadership, self-insight and development. In addition, you will receive a personal training budget to further shape your development. This is how we help you get the best out of yourself!

What we offer:

A 7-month contract — Full-time (40 hours per week
Hybrid working — Work from home and on-site, depending on what works best for you and the team.
International environment — You’ll join one of the largest banks in the Netherlands, with a diverse, global team.
Meaningful impact — Your work directly contributes to securing services used by millions.