Tech Lead Machine Learning Modeler, Financial Crimes

  • San Francisco, CA
  • Employees can work remotely
  • Full-time

Company Description

It all started with an idea at Block in 2013. Initially built to take the pain out of peer-to-peer payments, Cash App has gone from a simple product with a single purpose to a dynamic app, bringing a better way to send, spend, invest, borrow and save to our millions of monthly active users. With a mission to redefine the world's relationship with money by making it more relatable, instantly available and universally accessible, at Cash App you'll have the opportunity to make a real-world impact with your career.

Today, Cash App has thousands of employees around the world with a culture geared toward creativity, collaboration and impact. We’ve been a distributed team since day one, and continue to value working across time zones and continents both remotely and in our Cash App offices.

Our offices are great, but many of our roles can be done remotely from the countries where Block operates. We tailor our experience to champion our employees’ creativity and productivity wherever they are.

Check out our locations, benefits and more at

Job Description

The Financial Crimes Technology team at Cash App finds and reports financial crimes activity on Cash App. We work globally with partners in business, engineering, counsel and product to guarantee we are providing a safe user experience for our customers while minimizing or eliminating bad activity on our platform.

We are leveraging Machine Learning as an integral part of our toolkit to fulfill our mission. As Cash App scales, we are monitoring hundreds of billions of dollars in transactions across traditional payment and blockchain networks. We uncover and put an end to money laundering, fraud, and illegal activities before they impact our users. Additionally, we improve workflow and case tools, adding features that empower agent productivity and automate the high volume of monitoring.

This is currently an Individual Contributor role, but with significant leadership responsibilities that include envisioning, owning, and driving strategic roadmaps & priorities to completion by collaborating with cross functional stakeholders. The role may have the opportunity to progress into a people manager role in the future.

 You will:

  • Build classification and anomaly detection models to detect criminal & suspicious activity across Cash App’s p2p, banking, debit card, equities and crypto products

  • Develop customer risk rating models that facilitate efficient KYC reviews at onboarding and ongoing basis for CashApp accounts. 

  • Leverage innovative features and state of the art algorithms like Language Models & Graph Neural Networks to drive down false positives & improve agent productivity across Transaction Monitoring, and Sanctions queues

  • Deploy models to a production environment and build custom solutions as necessary to unblock the team

  • Use Python (numpy, pandas, sklearn, xgboost, Pytorch, TensorFlow etc.), Snowflake, Airflow, GCP, AWS services to get the job done


You Have: 

  • 6+ years of Machine Learning and software engineering experience

  • A graduate degree in computer science, data science, operations research, applied math, stats, physics, or a related technical field

  • End to end experience of building and deploying to production systems that are performant at scale

  • Experience leading small teams and/or owning & driving programs with cross functional stakeholders that have significant business impact

  • A curious, growth-oriented mindset and the ability to think in first principles to identify creative solutions that demonstrate value

  • Experience with advanced ML techniques like word embeddings, sequence modeling, and graph convolutional networks is a big plus

Additional Information

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 a proud equal opportunity employer. We work hard to evaluate all employees and job applicants consistently, without regard to race, color, religion, gender, national origin, age, disability, pregnancy, gender expression or identity, sexual orientation, citizenship, or any other legally protected class. 

We believe in being fair, and are committed to an inclusive interview experience, including providing reasonable accommodations to disabled applicants throughout the recruitment process. We encourage applicants to share any needed accommodations with their recruiter, who will treat these requests as confidentially as possible. Want to learn more about what we’re doing to build a workplace that is fair and square? Check out our I+D page

Additionally, we consider qualified applicants with criminal histories for employment on our team, and always assess candidates on an individualized basis.

Block, Inc. (NYSE: SQ) is a global technology company with a focus on financial services. Made up of Square, Cash App, Spiral, TIDAL, and TBD, we build tools to help more people access the economy. Square helps sellers run and grow their businesses with its integrated ecosystem of commerce solutions, business software, and banking services. With Cash App, anyone can easily send, spend, or invest their money in stocks or Bitcoin. Spiral (formerly Square Crypto) builds and funds free, open-source Bitcoin projects. Artists use TIDAL to help them succeed as entrepreneurs and connect more deeply with fans. TBD is building an open developer platform to make it easier to access Bitcoin and other blockchain technologies without having to go through an institution.

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