Staff Machine Learning Engineer (Modeling), Afterpay Risk

We started a movement in which everyone can win - shoppers, retailers, society and every person on our team. To play fair, trust people and reward them for doing the right thing. We see and feel the impact of our work as more and more people gain financial freedom and retailers grow across the globe.
Founded 10 years ago in Sydney, Australia, Afterpay has over 24 million active customers globally and more than 250,000 of the best retailers around the world including Anthropologie, Revolve, DSW, GOAT, Finish Line, Levi's, Mac Cosmetics, Ray-Ban and many others.
Afterpay is helping people spend responsibly! We empower customers to access the things they want and need, while still allowing them to maintain financial wellness and control, by splitting payments in four, for both online and in-store purchases. Afterpay is deeply committed to delivering positive outcomes for customers. Now under the Block ecosystem, we are focused on supporting our community of shoppers.
We trust in the next generation and share a vision of a more accessible and sustainable world in which people are rewarded for doing the right thing. Join a movement in which everyone can win.
The Role
Machine learning and data science are foundational to how Afterpay protects and scales its lending products-detecting fraud, mitigating abusive behaviors, and enabling more inclusive credit decisioning. Our integrated ecosystem of borrower behavior, repayment dynamics and merchant networks offers a rare opportunity to apply advanced modeling and analytical rigor to strengthen portfolio resilience while accelerating the precision and speed of underwriting.
As a technical and strategic leader, you will architect and build the ML systems that power fraud prevention and abuse mitigation across the lending lifecycle. You will partner closely with Product, Engineering, and Operations to drive platform-level improvements, influence portfolio and risk-appetite decisions, and strengthen the resilience of our lending ecosystem. You will also lead our shift toward AI-native, agentic risk systems that self-adapt, stay ahead of drift, and surface emerging fraud vectors before they scale.
This role is fully remote for candidates based in the US or Canada.
You Will

• Shape next-generation lending decision frameworks with advanced analytics, machine learning, and agentic automation to improve precision, adaptability, and speed.
• Analyze large and complex datasets to surface insights that influence underwriting strategy, strengthen ecosystem safeguards, and inform product direction.
• Lead signal discovery and deep experimentations to identify evolving risk patterns and inform the design of next-generation lending decision systems.
• Collaborate with Product, Engineering and Operations teams to design systems and features that enhance trust and portfolio health.
• Mentor and elevate fellow scientists and modelers, contributing to modeling standards, best practices, and technical excellence across the team.
• Exercise a high level of autonomy and ownership, driving solutions from problem framing and design through deployment and iteration.

You Have

• Bachelor's degree in a quantitative field (e.g., Mathematics, Statistics, Physics, Computer Science, Machine Learning); Master's or PhD preferred.
• 10+ years of industry experience in risk, fraud, credit underwriting, or another high-stakes decisioning domain.
• Deep expertise in machine learning methods, statistical modeling, and advanced analytical techniques.
• Strong analytical rigor with a deep testing mindset, including experience designing automated validation frameworks for models and decision logic.
• Strong communication skills, with the ability to explain complex concepts to both technical and non-technical stakeholders
• Hands-on experience with agentic workflows- LLM-based agents or automation components that enhance modeling velocity and decision reliability.

Technologies We Use and Teach

• SQL
• Python (NumPy, Pandas, Sklearn, TensorFlow, etc.)
• GitHub
• GCP/AWS

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 will consider qualified applicants with arrest or conviction records for employment in accordance with state and local laws and "fair chance" ordinances.
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 .
While there is no specific deadline to apply for this role, U.S. roles are typically open for an average of 55 days before being filled by a successful candidate. Please refer to the date listed at the top of this job page for when this role was first posted.
Block takes a market-based approach to pay, and pay may vary depending on your location. U.S. locations are categorized into one of four zones based on a cost of labor index for that geographic area. The successful candidate's starting pay will be determined based on job-related skills, experience, qualifications, work location, and market conditions. These ranges may be modified in the future.
To find a location's zone designation, please refer to this resource . If a location of interest is not listed, please speak with a recruiter for additional information.
Zone A:
$276,800 - $415,200 USD
Zone B:
$276,800 - $415,200 USD
Zone C:
$276,800 - $415,200 USD
Zone D:
$276,800 - $415,200 USD
Use of AI in Our Hiring Process
We may use automated AI tools to evaluate job applications for efficiency and consistency. These tools comply with local regulations, including bias audits, and we handle all personal data in accordance with state and local privacy laws.
Contact us here with hiring practice or data usage questions.
Every benefit we offer is designed with one goal: empowering you to do the best work of your career while building the life you want. Remote work, medical insurance, flexible time off, retirement savings plans, and modern family planning are just some of our offering. Check out our other benefits at Block.
Block, Inc. (NYSE: XYZ) builds technology to increase access to the global economy. Each of our brands unlocks different aspects of the economy for more people. Square makes commerce and financial services accessible to sellers. Cash App is the easy way to spend, send, and store money. Afterpay is transforming the way customers manage their spending over time. TIDAL is a music platform that empowers artists to thrive as entrepreneurs. Bitkey is a simple self-custody wallet built for bitcoin. Proto is a suite of bitcoin mining products and services. Together, we're helping build a financial system that is open to everyone.