Staff AI Modeler, Risk AutoML, Block

Block is one company built from many blocks, all united by the same purpose of economic empowerment. The blocks that form our foundational teams — People, Finance, Counsel, Hardware, Information Security, Platform Infrastructure Engineering, and more — provide support and guidance at the corporate level. They work across business groups and around the globe, spanning time zones and disciplines to develop inclusive People policies, forecast finances, give legal counsel, safeguard systems, nurture new initiatives, and more. Every challenge creates possibilities, and we need different perspectives to see them all. 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 work globally with partners in Product, Engineering and Operations to ensure that we are providing a safe user experience for our customers while minimizing or eliminating bad activity on our platform.

We are leveraging Generative AI (specifically Large Language Models) and Machine Learning as an integral part of our toolkit to fulfill our mission. As our platform scales, we monitor hundreds of billions of dollars in gross payment volume across traditional payment and blockchain networks. Our machine learning systems monitor and surface suspicious activity (fraudulent, suspicious, illegal activity and brand violations) for analyst review. Our systems also proactively block payments in real time where appropriate. Now, we are also leveraging generative AI technologies to improve analyst workflows and case review tools; by adding features that accelerate agent productivity and enable them to make faster, more informed and accurate decisions. In many instances, we automate the workflow end to end completely eliminating the need for manual reviews altogether. 

This is a new and significant opportunity to rethink and optimize Risk Operations at Block at scale. This is an IC role, but the Staff level has significant leadership responsibilities that include owning, and driving strategic roadmaps & priorities to completion by collaborating with relevant cross functional stakeholders.

You Will

• Experiment and deploy AI copilot and self-driving solutions at scale to improve analyst productivity and/or eliminate manual decision loops altogether
• Own the end to end pipeline including API calls to disparate data sources, advanced prompt tuning and/or model fine tuning, metrics and evaluation, and integrating Gen AI output into production case generation systems
• Leverage LLMs to accelerate label generation to alleviate cold start problems for traditional ML classification problems 
• Build classification models to detect illegal use of the app across the peer-to-peer, banking, card, equities and bitcoin products
• Leverage diverse data sets that include payment transactions, connected users and asset graphs, unstructured text data and user profile information to build ML and Generative AI models.  
• Work with the embedded Machine Learning/AI Engineers on the team and ML platform services to deploy models to the production environment and monitor ongoing performance
• Use Python ML stack, LLMs, Pytorch, Snowflake, Airflow based tools, data platform and cloud services (both GCP & AWS) to get the job done

You Have

• 5+ years of Machine Learning modeling experience. Full stack ML experience is strongly preferred
• A Masters or advanced degree in computer science, data science, operations research, applied math, stats, physics, or a related technical field
• 2+ yrs experience with AI engineering, Large language models, and a background in traditional NLP techniques is a strong plus for this role
• End to end experience of building and deploying ML/AI to production systems (batch and real time) that are performant at scale
• Experience of independently owning, influencing and driving programs with multiple cross functional stakeholders that have significant business impact
• Have a curious, growth-oriented mindset and the ability to think in first principles to identify creative solutions that demonstrate value

We’re working to build a more inclusive economy where our customers have equal access to opportunity, and we strive to live by these same values in building our workplace. Block is an equal opportunity employer evaluating all employees and job applicants without regard to identity or any legally protected class. We also consider qualified applicants with criminal histories for employment on our team, and always assess candidates on an individualized basis.

We believe in being fair, and are committed to an inclusive interview experience, including providing reasonable accommodations to disabled applicants throug