Posted Mar 10, 2026
As a Lead Machine Learning Engineer in AI Core Data Intelligence, you will:
Design and build scalable data ingestion pipelines that bring new datasets into our AI Core platform, ensuring reliable, efficient data flow from source to model training. - Implement data quality monitoring and validation systems that catch issues before they impact model performance, maintaining the health of datasets across our ML ecosystem. - Model new types of data into our foundation models. - Analyze the impact of new data sources on existing models, conducting experiments to measure performance improvements and guide data acquisition decisions. - Develop and maintain data preparation workflows that transform raw data into features ready for model training, working with distributed computing frameworks like Ray. - Tune and optimize machine learning models when new datasets are integrated, applying hyperparameter optimization and evaluating model performance improvements. - Collaborate with AI Core ML, Platform, and Infra teams to ensure seamless data flow across our ML infrastructure, from ingestion to model deployment. - Lead technical initiatives that improve our data engineering practices, setting standards for data quality, pipeline reliability, and model-data integration. - Mentor team members and contribute to hiring activities, helping build a strong and diverse team that drives innovation in AI infrastructure. #### Basic Qualifications
Typically 6+ years of experience in machine learning engineering, data engineering, or related fields with a strong track record of building production data and ML systems. - Proven experience designing and building data ingestion pipelines at scale, with expertise in distributed computing frameworks (Ray, Spark, or similar). - Strong background in applied machine learning, including model training, hyperparameter tuning, and performance evaluation. - Experience analyzing how data changes impact model performance, with the ability to design and run experiments to measure improvements. - Proficiency in Python for data engineering and ML workflows, with experience working with large-scale data processing systems. - Solid understanding of data quality principles and experience implementing monitoring, validation, and alerting systems. - Strong problem-solving skills with the ability to address complex, ambiguous problems requiring coordination across multiple teams. - Excellent communication skills, capable of explaining technical concepts to both technical and non-technical stakeholders. - Demonstrated leadership experience, including mentoring team members and contributing to technical decision-making. #### Preferred Qualifications
Experience with MLflow or similar model tracking and versioning systems. - Knowledge of foundation models, fine-tuning workflows, and transformer architectures. - Experience with data pipeline orchestration tools (Dagster, Airflow, or similar). - Background in financial services or fintech, understanding the unique data challenges in this domain. - Experience working in a fast-paced, high-growth environment with distributed teams. - Track record of reducing complexity in data systems and improving developer experience for ML teams. #### Our Benefits
Opportunity of earning equity at Nu
Medical Insurance
Dental and Vision Insurance
Life Insurance and AD&D
Extended maternity and paternity leaves
Nucleo - Our learning platform of courses
NuLanguage - Our language learning program
NuCare - Our mental health and wellness assistance program
Extended maternity and paternity leaves
401K
Saving Plans - Health Saving Account and Flexible Spending Account
Work-from-home Allowance
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/
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