Sr. Staff AI Engineer

About the role

About Zscaler Zscaler accelerates digital transformation to ensure our customers can be more agile, efficient, resilient, and secure. As an AI-forward enterprise, we are constantly pushing the envelope, leveraging the world s largest security data lake to power our cloud-native Zero Trust Exchange platform. This innovation protects our customers from cyberattacks and data loss by securely connecting users, devices, and applications in any location. Here, impact in your role matters more than title and trust is built on results. We say, impact over activity. We seek innovators who actively use AI to amplify their impact and who thrive in an environment where we leverage intelligent systems to stay ahead of evolving threats. We believe in transparency and value constructive, honest debate-we re focused on getting to the best ideas, faster. We build high-performing teams that can make an impact quickly and with high quality. To do this, we are building a culture of execution centered on customer obsession, collaboration, ownership, and accountability. We value high-impact, high-accountability with a sense of urgency where you re enabled to do your best work and embrace your potential. If you re driven by purpose, thrive on solving complex challenges, and want to be part of the team that s helping to secure the AI age, we invite you to bring your talents to Zscaler and help shape the future of cybersecurity.Role We are looking for a Sr Staff AI Engineer to join our Red Teaming department in a hybrid capacity in Zagreb or Split, Croatia, reporting to the Manager, Machine Learning. We are looking for a technically exceptional AI Engineer to join our Croatia-based team and take a leading role in building the products that define how AI systems are secured. You will not only execute red team work, but also own projects end-to-end, from technical architecture through delivery, and help set the strategic direction of what we build. What you ll do (Role Expectations) Lead the design, planning, and hands-on execution of red team exercises against generative AI systems, probing for prompt injection, adversarial inputs, and broader misuse vectors Continuously track advances in AI security, adversarial ML, and responsible/ethical AI to strengthen methodologies and guardrails Convert the latest academic and industry findings into production-grade tools, test cases, and evaluation procedures, developing and validating new techniques for AI-focused red teaming while raising the engineering quality bar across the team Define measurable KPIs and success criteria for red team engagements, and report findings with clear remediation guidance Own the technical vision, architecture, and end-to-end development of red teaming tools and products, making the core engineering decisions and driving them through to production Who You Are (Success Profile) You act like an owner. Your passion for the mission fuels your bias for action. You operate with integrity because you genuinely care about the outcome. You adapt to what s needed, navigating seamlessly between high-level strategy and hands-on execution. You are a problem-solver. You seek out challenges because you are energized by finding solutions, knowing that solving the hard problems delivers the biggest impact. You are a learner. You have a true growth mindset and never stop developing yourself, actively seeking feedback to become a better partner and a stronger teammate. You love what you do and you do it with purpose. You are driven by innovation. You have a deep curiosity for how things work and are energized by solving complex technical challenges. You believe in the power of technology to accelerate transformation and are always looking for a better, more secure, and scalable way. You are a pragmatic builder. You are obsessed with creating, iterating, and shipping. You aren t afraid to roll up your sleeves and build the first version yourself, balancing the drive for technical excellence with the need to deliver value to users quickly. What We re Looking for (Minimum Qualifications) B.S. in Computer Science, Engineering, or equivalent practical experience Strong Python skills with hands-on experience building and shipping production-grade software beyond scripting, plus practical experience working with LLMs Demonstrated track record of leading technical projects end-to-end, owning architecture and design decisions through to delivery Working knowledge of cybersecurity and/or AI security concepts such as prompt injection, adversarial ML, and LLM application risks What Will Make You Stand Out (Preferred Qualifications) Experience shaping product direction or owning a product/roadmap, translating research insights into shipped tools Strong understanding of core ML/AI concepts and theory such as model architectures, training and fine-tuning, evaluation methods, and how modern LLMs work under the hood Hands-on experience with adversarial ML/AI, attacking, probing, or hardening mod