Senior Machine Learning Engineer (Modeling), Bitcoin Risk

About the Team

We’re looking for an experienced Machine Learning Engineer to join our Risk Modeling team, focused on Bitcoin products. This team is responsible for detecting and responding to fraudulent and illicit Bitcoin activity across Cash App and Square.

In this role, you’ll serve as the DRI for Bitcoin risk modeling—building end-to-end strategy, model development, and execution across Block’s Bitcoin ecosystem. You’ll operate with a high degree of autonomy, partnering closely with Product, Engineering, and Compliance to shape how risk and compliance controls scale as we launch new Bitcoin products.

You Will:

• Partner with product, engineering, data science, policy, and operations to design and productionize ML-driven risk solutions at scale
• Own end-to-end machine learning systems — from problem definition and modeling to deployment, monitoring, and iteration
• Lead technical decision-making within your workstreams and influence ML strategy and planning
• Build tooling and processes that improve the speed, reliability, and impact of the ML development lifecycle
• Apply modeling techniques and third-party data sources to improve detection and decision-making
• Investigate emerging fraud, abuse, and risk patterns to proactively inform product safeguards and policy
• Collaborate closely with ML platform and engineering teams to ensure models operate reliably in real time and at scale
• Mentor teammates and contribute to an inclusive engineering culture
  
  

You Have:

• 7+ years of industry experience in machine learning, applied AI, or related fields
• Bachelor’s degree in a quantitative field (Computer Science, Engineering, Statistics, Physics, Applied Math); Master’s or PhD preferred
• Prior experience with Bitcoin or crypto is helpful, but not required
• Proven experience independently designing, deploying, and maintaining ML solutions in production
• Experience influencing technical direction and collaborating with cross-functional partners at scale
• Strong communication skills, sound judgment, and an ownership mindset
• Curiosity and alignment with Block’s mission of economic empowerment
  
  

Technologies We Use and Teach

• Python (NumPy, Pandas, scikit-learn, XGBoost, PyTorch, TensorFlow/Keras)
• PySpark, MLflow, workflow orchestration tools (Airflow, Prefect)
• GCP (Vertex AI), AWS
• Snowflake, MySQL, Tableau, Mode
• Containerization, CI/CD, and production ML best practices