Senior Staff Engineer, AI Core

About Us Nu is one of the largest digital financial platforms in the world, with more than 127 million customers across Brazil, Mexico, and Colombia. Guided by our mission to fight complexity and empower people, we are redefining financial services in Latin America and this is still just the beginning of the purple future we're building. Listed on the New York Stock Exchange (NYSE: NU), we combine proprietary technology, data intelligence, and an efficient operating model to deliver financial products that are simple, accessible, and human. Our impact has been recognized by global rankings such as Time 100 Companies, Fast Company's Most Innovative Companies, and Forbes World's Best Bank. Visit our institutional page https://international.nubank.com.br/careers/ About the Role At Nu, the AI Private Banker is our intelligent financial partner that helps millions of customers understand their finances, make confident decisions, and take action seamlessly. As a Staff Software Engineer on this team, you'll define the technical architecture that powers conversational AI, recommendation engines, and personalized financial experiences across mobile and web. You'll own the full stack from Flutter mobile apps that reach millions of users to distributed backend systems that process real-time recommendations and conversational AI interactions. This isn't just about building features; it's about creating the engineering foundation that makes financial empowerment accessible at scale. Here, every technical decision you make directly impacts how millions of people experience financial guidance. You'll work at the intersection of banking and frontier AI, building systems that are both innovative and reliable. Behind every product interaction, there are curious minds redefining what's possible—and you'll be one of them. You'll be responsible for Lead the technical architecture and design decisions for AI Private Banker's full-stack platform, ensuring scalability and performance across mobile and backend systems. Build and maintain Flutter mobile applications that deliver seamless conversational AI experiences to millions of users across iOS, Android, and Web. Design and implement distributed backend services that power recommendation engines, conversational AI integration, and real-time personalization. Collaborate with product, design, and data teams to translate ambitious product goals into clear, phased technical roadmaps. Drive engineering best practices across the team through code reviews, technical mentorship, and architectural guidance. Own the technical strategy for deploying and maintaining a unified user experience across multiple platforms and markets. Integrate AI/ML model outputs into consumer-facing applications, ensuring real-time performance and reliability. Make decisive technical trade-offs that balance innovation, scalability, and operational excellence. We are looking for a person who has Required Experience as a Sr. Staff/Staff Engineer shipping complex, large-scale consumer-facing mobile applications. Strong track record of designing, building, and operating high-throughput, fault-tolerant backend services using microservices architecture and event-driven design. Proven ability to take complete technical ownership of a major product area, making informed trade-offs on architecture and implementation. Experience working with data systems, APIs, and pipelines necessary to power AI/ML outputs within user interfaces. Track record of leading technical initiatives and mentoring other engineers on architecture, performance, and operational excellence. Nice to have Experience in the FinTech or highly regulated industry. Familiarity with cloud-native development (AWS). Proficiency in one or more backend languages suitable for high-scale applications (e.g., Go, Java, Python, Clojure). Experience building conversational AI interfaces or recommendation systems. Track record of scaling mobile applications across multiple global market