Machine Learning Engineer

About The Company Block, Inc. is a leading technology company dedicated to building innovative financial products that empower individuals and businesses worldwide. With a diverse portfolio of brands including Square, Cash App, Afterpay, TIDAL, Bitkey, and Proto, the company aims to increase access to the global economy through cutting-edge technology solutions. Committed to fostering an inclusive and dynamic work environment, Block leverages its expertise in payments, commerce, and financial services to create seamless, secure, and scalable platforms that serve millions of users globally. The company’s culture emphasizes innovation, collaboration, and integrity, ensuring that its teams are equipped to tackle complex challenges and deliver impactful solutions.

About The Role As a Staff Machine Learning Engineer on the Predictive Systems team, you will play a pivotal role in shaping the technical strategy for machine learning and decisioning systems that address risk, fraud, and abuse across Block’s suite of products. Acting as a domain owner for platforms such as Cash App, Square, and Afterpay, you will influence how AI solutions are architected, integrated, and operationalized to support scalable, real-time risk management. Your leadership will ensure that risk functions act as enablers for rapid product development while maintaining a trusted ecosystem. You will oversee the entire lifecycle of production ML systems, orchestrating data, features, models, and controls into robust defenses. Operating at an ecosystem level, you will establish durable abstractions and decisioning patterns that standardize risk strategies across multiple domains. Additionally, you will contribute to the evolution of Block’s core ML infrastructure, ensuring it meets the demands of high-volume, complex decisioning workloads.

Qualifications

• Extensive experience designing and leading large-scale machine learning systems with organizational impact.
• Proven ability to set technical vision and align multiple teams and disciplines.
• Deep understanding of ML systems, data platforms, and real-time decisioning at scale.
• Strong judgment in balancing risk, trust, and product velocity considerations.
• Experience mentoring senior engineers and developing future technical leaders.
• Systems-level mindset with a focus on durable, high-leverage solutions.
• Proficiency in programming languages such as Python, Java, and Kotlin.
• Experience with ML frameworks like TensorFlow and PyTorch.
• Familiarity with cloud and data technologies including AWS, Databricks, Kubernetes, MySQL, DynamoDB, Kafka, and Spark.

Responsibilities

• Act as a technical lead across multiple Risk ML engineering teams, guiding the application of ML and AI to fraud, abuse, and risk decisioning.
• Design and enhance real-time and batch ML systems leveraging Block’s core ML platforms for scalable risk solutions.
• Drive architectural decisions related to feature utilization, contextual signals, and ML-driven controls in collaboration with modeling, product, and platform teams.
• Translate ambiguous risk problems into clear technical strategies and actionable plans.
• Lead cross-team initiatives to integrate new data sources, signals, and event hooks into production risk systems.
• Establish standards for data quality, observability, and correctness in ML inputs and decision outputs.
• Provide technical leadership during emerging threat scenarios, guiding rapid mitigation efforts while safeguarding system health.
• Influence and improve ML and AI engineering practices across Risk teams to enhance consistency, reliability, and development velocity.

Benefits

• Comprehensive healthcare coverage including Medical, Vision, and Dental insurance.
• Health Savings Account (HSA) and Flexible Spending Account (FSA).
• Retirement plans with company matching contributions.
• Employee Stock Purchase Program to participate in company growth.
• Wellness programs, including mental health support, access to financial planners, and a monthly wellness allowance.
• Paid parental and caregiving leave policies.
• Paid time off, including holidays and sick leave, with flexible options for exempt employees.
• Access to learning and development resources to support career growth.
• Paid life insurance, accidental death & dismemberment (AD&D), and disability benefits.
• Eligibility to participate in Block’s equity plans and potential sign-on bonuses.

Equal Opportunity

Block, Inc. is an equal opportunity employer. We are committed to evaluating all employees and job applicants based solely on the core competencies required for each role, without regard to any legally protected characteristics. We strive to create an inclusive interview experience and provide reasonable accommodations to disabled applicants throughout the recruitment process. If you require accommodations, please share your needs with your recruiter. We believe diversity and inclusion drive innovation and are dedicated to fostering a workplace where everyone can thrive.