Senior Machine Learning Engineer, Risk Modeling

About the role

We're hiring Senior and Staff Machine Learning Engineers to join Block's Risk Machine Learning organization. Teams apply ML at massive scale to detect, prevent, and reduce fraud and abuse across Cash App and Square.

Responsibilities

• 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 state-of-the-art 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

Requirements

• 8+ 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
• Proven experience independently designing, deploying, and maintaining ML solutions in production
• Strong familiarity with techniques such as tree-based models, deep learning, transfer learning, or reinforcement learning
• 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

Qualifications

• Proven track record of success in applying machine learning to solve complex problems
• Experience with Python (NumPy, Pandas, scikit-learn, XGBoost, PyTorch, TensorFlow/Keras)
• Experience with PySpark, MLflow, workflow orchestration tools (Airflow, Prefect)
• Experience with GCP (Vertex AI), AWS, Snowflake, MySQL, Tableau, Mode
• Experience with containerization, CI/CD, and production ML best practices

Skills

• Adversarial ML
• NLP/LLMs
• Credit modeling
• Model validation

Benefits

Every benefit we offer is designed with one goal: empowering you to do the best work of your career while building the life you want. Remote work, medical insurance, flexible time off, retirement savings plans, and modern family planning are just some of our offerings.

Pay

Competitive compensation package based on experience and qualifications.

Schedule

Flexible work schedule to accommodate your needs.

Contact us

To learn more about this opportunity, please contact us here with hiring practice or data usage questions.