Senior Security Engineer - Application Security- BR - 2026

About Nu Nu is the leading digital bank in Latin America, serving 135 million customers across Brazil, Mexico, and Colombia. The company has been leading an industry transformation by leveraging data and proprietary technology to develop innovative products and services. Guided by its mission to fight complexity and empower people, Nu caters to customers’ complete financial journey, promoting financial access and advancement with responsible lending and transparency. The company is powered by an efficient and scalable business model that combines low cost to serve with growing returns. Nu’s impact has been recognized in multiple awards, including Time 100 Most Influential Companies, Fast Company’s Most Innovative Companies, and Forbes World’s Best Banks. Visit our Institutional Page About the team The Application Security team is part of the Information Security area. The team focuses on proactive hunting for and mitigating potential security threats on Nubank to protect our customers' financial assets and data. For that, we perform many tasks such as embedding and developing security controls on the applications, supporting all engineers during the software development lifecycle. Our AppSec team is at the forefront of enabling secure innovation at Nubank. We believe security should be an enabler, not a blocker, and we build scalable solutions to help developers ship secure code without friction. From designing AI-powered threat modeling tools to automating security in CI/CD, our work impacts every Nubanker engineer. About the role As a Security Engineer in our Application Security (AppSec) team, you will be part of the group responsible for enabling secure software development practices across Nubank’s entire engineering organization. We support teams working with a diverse technology stack – including Clojure, Python, Go for backend and Kotlin, Swift, Dart for mobile – by embedding security into their SDLC. This role is ideal for someone with a strong foundation in application security concepts, who enjoys working closely with engineering teams to drive security best practices, and who has a keen interest in emerging areas such as AI security and threat modeling. Your mission will include helping design and deploy security tools in our CI/CD pipelines (SAST, DAST, SCA), performing threat modeling for new projects, supporting security reviews, and contributing to the automation of AppSec processes, including those involving new AI technologies like Model Context Protocol (MCP) Servers and agents. You'll be responsible for Embed security practices into the SDLC across backend, mobile, and web applications. Deploy and maintain security tools (SAST, DAST, SCA, MAST) in CI/CD pipelines. Perform threat modeling and security reviews for new and existing projects. Develop scripts and tools (Python, Go, Bash) to automate security checks and processes. Collaborate with engineering teams to explain and remediate vulnerabilities. Support AI-related security initiatives, ensuring safe adoption of ML/AI features in products. Contribute to the evolution of internal security guidelines and baselines. Participate in cross-functional discussions to align security requirements with business goals. We are looking for a person who has Must-have Solid understanding of application security concepts and secure software development practices. Hands-on experience with CI/CD pipelines and implementing security tools (e.g., SAST, DAST, SCA). Knowledge of scripting/programming with commonly used languages like Python, Go, bash, etc for automation and tooling. Familiarity with container security tools (e.g., Trivy, Aqua). Experience working with modern software architectures: Web, Mobile, APIs, and MCPs. Strong communication and collaboration skills to work with multi-disciplinary teams. Nice to Have Previous experience conducting security assessments in distributed systems environments. Experience with tools like Semgrep, Fortify, Checkmarx, Veracode. Experience with pipeline tools like Github Actions, Gitlab Workflow, others. Experience with AI security concepts and emerging AI/ML security risks. Familiarity with threat modeling methodologies (e.g., STRIDE, PASTA, OWASP Threat Dragon). Knowledge of regulatory and compliance requirements relevant to financial services. Location São Paulo, Brazil Campinas, Brazil Rio de Janeiro, Brazil Belo Horizonte, Brazil 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/ 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.