ABOUT NU Nu serves more than 140 million customers, guided by a mission to fight complexity and empower people. The company has been leading an industry transformation through innovative products and human-centered services. Proprietary technology and data at scale power Nu’s digital platform, built to promote financial access, advancement, and transparency. Its business model thrives on customer love and lower costs, feeding a flywheel of growth and profitability. Visit our Institutional Page https://www.nu.com/2026-en About the role We are looking for a Senior Security Engineer to work closely with our teams to strengthen the security and resilience of our AI ecosystem. In this role, you will identify and assess security risks across machine learning models and Generative AI applications, design and implement security controls, and help build security frameworks and tooling for the safe adoption of AI at scale. You will partner with engineering teams to integrate security throughout the AI development lifecycle, automate security assessments and controls, and contribute to the continuous evolution of our AI security practices. This role combines hands-on security engineering, risk analysis, and applied AI security, requiring strong technical expertise, sound judgment, and a proactive mindset to help ensure the secure and responsible use of AI technologies. Main Responsibilities - Identify and analyze vulnerabilities, providing insights and recommendations for mitigation; - Contribute to the development and implementation of cutting-edge security frameworks, ensuring the responsible and secure usage within our AI ecosystem; - Work closely with development teams to integrate security measures into the AI development lifecycle; - Assist in incident response planning specific to AI-related security incidents and participate in simulations to test response effectiveness; - Develop and integrate tools to automate security assessments and controls; - Proactively seek knowledge and engage in research and development initiatives to support innovation; - Raise Nubank awareness towards safe AI usage. Must Have - Knowledge of security frameworks, such as OWASP; - Programming skills in languages commonly used in machine learning (e.g., Python); - Proactive mindset with the ability to analyze complex systems and identify potential security risks; - Strong communication skills to effectively convey complex security concepts to technical and non-technical stakeholders. - Hands-on experience with CI/CD pipelines and implementing security tools (e.g., SAST, DAST, SCA). - Experience with high scalability environments. - Experience in zero-trust and regulated environments. Nice to Have - Experience with AI frameworks and libraries (e.g. PyTorch, TensorFlow); - Expertise with automation programming languages (e.g. Bash, Ansible, Go); - Knowledge of cloud infrastructure technologies (e.g. AWS, K8S, Terraform); - Knowledge of Machine Learning and Generative AI concepts and technologies (e.g. HuggingFaces, MCP). Role Location Hybrid: Belo Horizonte, Rio de Janeiro, São Paulo, Campinas - SP. Our Benefits - Chance of earning equity at Nubank - Food/ Meal Card (Vale-Refeição and/or Vale Alimentação) - Public Transportation Commuting Benefit (Vale-Transporte) - NuCare – Psychological, Financial and Legal Assistance Program - Life Insurance - Medical Plan - Dental Plan - NuLanguage – Language Course Program - Nucleo - Our learning platform of courses - Extended Parental Leave - Daycare Allowance - Parental Consultancy - Work-from-home Allowance - Gym Partnerships - 30 days of paid vacation - Relocation Assistance Package, if applicable Work Model for this Role Hybrid 2-3 times/week: Our hybrid work model brings us to the office at least twice a week, on strategic days designed to maximize team connection and collaboration. For more details, visit https://building.nubank.com/nu-hybrid-work-model/ Explore how we build technology at Nubank: 🔗 https://building.nubank.com.br/building.nubank.com.br http://building.nubank.com.br ↗ 🎥 https://www.youtube.com/@building.nubankyoutube.com/@building.nubank http://youtube.com/@building.nubank ↗ 🎧 Listen to our stories on Spotify https://open.spotify.com/show/4hAJnAkYKXl42hLXa4LmVQ ↗ Our recruitment process may involve the use of artificial intelligence–enabled tools, such as automated interview transcription and analysis, to support the evaluation process. Artificial intelligence is not used to make final hiring decisions; all decisions are made by human reviewers. To maintain a consistent and fair process for every candidate, Nu does not provide individualized technical feedback. See how our policy works here https://script.google.com/a/macros/nubank.com.br/s/AKfycbwvrewE58oGSbRWIVv8CyCWN68GLxpPVsfYYXv-ZHg94QFsTJmi82rF1x0yt-OTs2W0DQ/exec