Lead Machine Learning Engineer, Risk AI

The Role
The Risk AI team's mission is to develop cutting-edge deep learning-based signals and learned representations for Risk ML models. Our focus is on exploring, developing, and implementing state-of-the-art (SOTA) alternatives to traditional feature-based machine learning methods. By leveraging the latest advancements in AI, we aim to enhance real-time evaluation pipelines used by the Risk ML team to detect and prevent fraudulent transactions and activities. Cash App holds people's money, and maintaining customers' trust is absolutely essential to our brand. Preventing scams and fraud is a major component of building that trust. The Risk AI team is at the forefront of this effort, utilizing SOTA approaches to drive innovation and protect our users from emerging threats.
You Will

• Design, build and maintain Machine Learning systems that enable us to flag fraudulent activities in real-time
• Work hand-in-hand with ML Modellers to identify and integrate new data sources, heuristics and models
• Solve challenging technical problems at scale, collaborating with colleagues located across the globe
• Own your solutions from design through to operation: we all share the pager!
• Lead the conception, design, and implementation of large-scale experiments to validate novel ideas rapidly and comprehensively
• Apply the latest theoretical advancements to enhance existing products, processes, and technologies, ensuring they remain at the forefront of the industry
• Engage in the creation of experiments, prototyping, and architectural design, contributing to a diverse range of computer science domains such as machine learning, data mining, natural language processing, and performance analysis
• Take the lead in designing systems, data structures, frameworks, and evaluation metrics for research solution development
• Conduct experiments aligned with research inquiries, employing simulations and prototypes to assess the outcomes

You Have

• ~8 years of Software Engineering + some professional ML experience
• A track record of solving business problems with technology and proven experience successfully taking ownership of an end-to-end solution
• Have lead complex, multi person projects
• Work autonomously in a fast paced, ambiguous and unpredictable environment
• Be naturally curious & eager to learn
• Work creatively, taking initiative and leading when required
• Grow your solutions, maintaining and fixing them as necessary
• Communicate via clear and concise writing to facilitate asynchronous collaboration across multiple time zones
• Reason about complex, distributed systems at high scale
• Proficiency in machine learning techniques, experimental design and data engineering
• Strong programming skills in languages such as Python, TensorFlow, or PyTorch.

Technologies We Use and Teach

• Python, Java, Kotlin
• Onnx/PyTorch, LightGBM/XGBoost
• Kubernetes, AWS
• Datadog, SumoLogic
• Hibernate, MySQL, Cassandra DB, DynamoDB
• HTTP, JSON, gRPC, Protocol Buffers
• Kafka, event-driven microservice architecture

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 identity or 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.
Block is a globally distributed company and this role will require working with other employees in multiple time zones. You may be required to perform work outside of normal business as part of this role.
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.