Lead ML Data Engineer (AI/Machine Learning)

TL;DR

Lead ML Data Engineer (AI/Machine Learning): Building and optimizing scalable data infrastructure and feature pipelines for state-of-the-art foundation models with an accent on data quality, ingestion, and feature preparation. Focus on designing, training, and shipping transaction classification models that power critical customer experiences across the company.

Location: Hybrid (2-3 times/week) in North American offices: Palo Alto, USA; Miami, USA; New York, USA; Durham, USA; or Toronto, Canada. Relocation assistance available.

Company

Nu is one of the largest digital financial platforms in the world, serving over 127 million customers across Brazil, Mexico, and Colombia, redefining financial services through proprietary technology and data intelligence.

What you will do

• Design and build scalable data ingestion pipelines for the AI Core platform.
• Implement data quality monitoring and validation systems for ML datasets.
• Model new data types into foundation models and analyze their impact on existing models.
• Develop and maintain data preparation workflows using distributed computing frameworks.
• Tune and optimize machine learning models with new datasets.
• Collaborate with ML, Platform, and Infra teams to ensure seamless data flow.

Requirements

• 6+ years in ML engineering or data engineering with production data and ML systems experience.
• Proven experience designing and building scalable data ingestion pipelines with distributed computing (Ray, Spark).
• Strong background in applied machine learning, including model training and evaluation.
• Proficiency in Python for large-scale data processing and ML workflows.
• Solid understanding and implementation experience of data quality principles, monitoring, and alerting systems.
• Demonstrated leadership, mentoring, and technical decision-making experience.
• Work model: Hybrid (2-3 times/week) in one of the North American offices: Palo Alto, USA; Miami, USA; New York, USA; Durham, USA; or Toronto, Canada.
• Relocation assistance is available.

Nice to have

• Experience with MLflow or similar model tracking systems.
• Knowledge of foundation models, fine-tuning, and transformer architectures.
• Experience with data pipeline orchestration tools (Dagster, Airflow).
• Background in financial services or fintech.
• Experience in fast-paced, high-growth, distributed environments.

Culture & Benefits

• Opportunity to earn equity.
• Medical, Dental, Vision, and Life Insurance.
• Extended maternity and paternity leaves.
• Learning platforms (Nucleo, NuLanguage) and mental wellness assistance (NuCare).
• 401K and Saving Plans (Health Saving Account, Flexible Spending Account).
• Work-from-home allowance.