The Role

Block's Chargeback Risk Machine Learning team builds machine learning models and systems to detect, intervene on, and reduce fraudulent activity across Block's Cash App and Square ecosystems. The work safeguards these ecosystems from financial loss and provides trustworthy financial experiences for millions of customers and sellers.

You Will

• Partner with product, engineering, data science, policy, and operations to design and productionize ML-driven solutions to fight fraud at scale.
• Become a risk domain expert and lead strategy and planning on your workstreams.
• Develop tooling and processes to improve the effectiveness and speed of the ML development lifecycle.
• Investigate and use state-of-the-art modeling algorithms and third-party data sources to boost model performance.
• Contribute positively to team culture as a collaborative, empathetic, and reliable teammate.

You Have

• 3+ years of machine learning experience.
• A degree (preferably graduate level) in Computer Science, Engineering, Statistics, Physics, Applied Math or related technical field.
• Hands-on experience independently designing, deploying, and troubleshooting ML solutions using methods such as tree-based models, deep learning, transfer learning, or reinforcement learning.
• Proficiency in modern ML stacks such as PySpark, PyTorch, MLflow, GCP Vertex AI, Workflow orchestration tools (Airflow, Prefect).
• Proficiency with containerization, cloud platforms (AWS, GCP), and CI/CD practices.
• Experience collaborating with cross-functional teams to prioritize, scope, and deploy ML/AI solutions at scale.
• Experience mentoring teammates and providing constructive feedback.
• A natural sense of curiosity and alignment with Block's mission of economic empowerment.