Since we opened our doors in 2009, the world of commerce has evolved immensely, and so has Square. After enabling anyone to take payments and never miss a sale, we saw sellers stymied by disparate, outmoded products and tools that wouldn’t work together.

So we expanded into software and started building integrated, omnichannel solutions – to help sellers sell online, manage inventory, offer buy now, pay later functionality, book appointments, engage loyal buyers, and hire and pay staff. Across it all, we’ve embedded financial services tools at the point of sale, so merchants can access a business loan and manage their cash flow in one place. Afterpay furthers our goal to provide omnichannel tools that unlock meaningful value and growth, enabling sellers to capture the next generation shopper, increase order sizes, and compete at a larger scale.

Today, we are a partner to sellers of all sizes – large, enterprise-scale businesses with complex operations, sellers just starting, as well as merchants who began selling with Square and have grown larger over time. As our sellers grow, so do our solutions. There is a massive opportunity in front of us. We’re building a significant, meaningful, and lasting business, and we are helping sellers worldwide do the same. .

The Role

Risk ML Platform protects Square and our customers by safeguarding over $25B in payments from fraud and payment disputes. We build machine learning systems to detect potential fraud threats and provide tools for data scientists to develop models that combat fraud. Our mission is to protect Square, protect our customers, and simplify what can be a complex and sometimes challenging process for everyone.

We are seeking an experienced engineer to join the Risk ML Platform. In this role, you will work across the entire machine learning lifecycle, from training to deployment and model interpretability. As a platform engineer, you will collaborate closely with internal customers to understand their needs and translate those into scalable software solutions.

We're looking for someone with experience as both a software engineer and in machine learning, as we operate at the intersection of these two fields. Experience in building platforms is highly preferred. Beyond that:

You Will

• Develop a scalable AI platform that enable us to flag fraudulent activities
• Work hand-in-hand with ML Modelers to identify and integrate new data sources, heuristics and model types
• 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

You Have

• 3+ years of experience in training and deploying ML models, developing ML software, and shipping customer-facing ML products. 
• Deep understanding of modern ML techniques (e.g. Large Language Models) and the ML lifecycle from data gathering, training, model evaluation, MLOps, and productionizing models.
• Experience with large-scale distributed systems built around ML
• Ability to produce production-quality code and services incorporating testing, evaluation, monitoring, and exquisite documentation, as well as the ability to quickly adapt to a new domain, hack MVP’s, and iterate to improve product.
• Experience using any of the major cloud vendors for high scale production use cases
• Strong communication skills (verbal and written) with technical and non-technical stakeholders.

Technologies We Use and Teach

• Python, Java
• LightGBM/XGBoost, Onnx/PyTorch
• Kubernetes, AWS SageMaker, GCP Vertex
• Datadog, Sentry
• 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 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 throughout the recruitment process. If you require an accommodation, let your recruiter know.

Want to learn more about what we’re doing to build an inclusive workplace? Check out our Inclusion & Diversity page.