Senior Machine Learning Modeler, Risk Automation ML

Block; San Francisco (CA); Remote; USD 217,000 - 344,000; Full time

Job summary

An innovative company is seeking a Machine Learning expert to enhance fraud detection on their platforms. In this strategic role, you'll leverage Generative AI and Machine Learning to optimize decision-making and automate processes. With a focus on collaboration and leadership, you'll manage the ML pipeline, ensuring the safety of millions of transactions. Join a forward-thinking team committed to economic empowerment and inclusive policies, where your contributions will directly impact user experience and security.

Benefits

Health Insurance

Flexible Time Off

Retirement Plans

Family Planning Support

Remote Work Options

Qualifications

• 5+ years of experience in Machine Learning modeling.
• Masters or higher in relevant fields like computer science or data science.

Responsibilities

• Manage the end-to-end ML pipeline for fraud detection.
• Collaborate with ML engineers to deploy and monitor models.

Skills

Machine Learning

Python

AI Engineering

NLP Techniques

Data Integration

Decision-Making

Education

Master's in Computer Science

Master's in Data Science

Tools

PyTorch

Snowflake

GCP

AWS

Airflow

Job description

Remote

Bay Area, CA, US

Posted Date: 05/01/25

Posted 5 days ago

The Company

Block is a company built from many blocks, all united by the same purpose of economic empowerment. The foundational teams — People, Finance, Counsel, Hardware, Information Security, Platform Infrastructure Engineering, and more — support and guide the organization across business groups and around the globe, fostering inclusive policies, financial forecasting, legal counsel, system security, and innovative initiatives. We value diverse perspectives to recognize and seize opportunities. Bring yours to Block.

The Role

The Risk Automation ML team at Block detects, prevents, and reports fraudulent, illegal, and suspicious activity on CashApp and Square. We collaborate globally with Product, Engineering, and Operations teams to ensure a safe user experience while minimizing bad activity. We leverage Generative AI (Large Language Models) and Machine Learning to enhance our capabilities. As our platform scales, we monitor hundreds of billions of dollars in payment volume, using ML systems to surface suspicious activity and proactively block payments. We are now integrating generative AI to improve analyst workflows, accelerate decision-making, and automate processes to eliminate manual reviews.

This is a strategic role with leadership responsibilities, including owning and driving roadmaps and priorities in collaboration with cross-functional stakeholders.

You Will

• Experiment with and deploy AI copilot and autonomous solutions to enhance analyst productivity and decision-making
• Manage the end-to-end ML pipeline, including data integration, prompt tuning, model fine-tuning, and system deployment
• Use LLMs to accelerate label generation, addressing cold start issues for traditional ML models
• Build classification models to detect illegal activities across various financial products
• Utilize diverse data sources—transactions, user profiles, unstructured text, asset graphs—for ML and AI models
• Collaborate with ML engineers to deploy and monitor models in production environments
• Apply Python ML tools, LLMs, PyTorch, Snowflake, Airflow, and cloud services (GCP & AWS) to achieve objectives

You Have

• 5+ years of experience in Machine Learning modeling, with full-stack ML experience preferred
• Masters or higher in computer science, data science, operations research, applied math, physics, or related fields
• 2+ years experience with AI engineering, Large Language Models, and NLP techniques
• End-to-end experience deploying ML/AI systems at scale, in real-time and batch environments
• Proven ability to lead programs with cross-functional teams impacting business outcomes
• A curious, growth-oriented mindset and first-principles thinking for innovative solutions

Technologies We Use

• Python (NumPy, Pandas, sklearn, PyTorch), with occasional Kotlin and Java
• Snowflake, GCP, AWS, Airflow

We are committed to building an inclusive economy and workplace. Block is an equal opportunity employer, evaluating all applicants without regard to legally protected classes. We consider qualified applicants with criminal histories on an individualized basis. We strive for a fair and inclusive interview process, providing accommodations as needed. Learn more about our efforts on our I+D page.

We consider qualified applicants with arrest or conviction records, in accordance with laws and ordinances.

Our pay ranges vary by location, based on market data and job-related skills:

• Zone A: USD $228,700 - $343,100
• Zone B: USD $217,300 - $325,900
• Zone C: USD $205,900 - $308,900
• Zone D: USD $194,500 - $291,700

Our benefits support your career and personal life, including remote work, health insurance, flexible time off, retirement plans, and family planning. See more on our benefits page.

Block, Inc. builds technology to increase access to the global economy through brands like Square, Cash App, Afterpay, TIDAL, Bitkey, and Proto. Together, we aim to create an open financial system for everyone.