Senior Machine Learning Engineer, Risk Modeling
Block, Inc. is a technology company building tools for economic empowerment, operating a portfolio of financial brands including Square, Cash App, Afterpay, TIDAL, Bitkey, and Proto. It serves sellers, consumers, artists, and bitcoin users through payments, banking, buy-now-pay-later, music streaming, and bitcoin self-custody and mining products.
About Block, Inc.
Block, Inc. builds technology aimed at increasing access to the global economy. Its brands each unlock different aspects of the economy: Square makes commerce and financial services accessible to sellers; Cash App is an easy way to spend, send, and store money; Afterpay (Clearpay in the UK) helps customers manage spending over time; TIDAL is a music platform empowering artists as entrepreneurs; Bitkey is a self-custody bitcoin wallet; and Proto builds open, accessible bitcoin mining hardware and services. Block has been a long-time advocate for bitcoin, integrating bitcoin buying/selling and Lightning Network payments into Cash App and Square, funding open-source bitcoin infrastructure through Spiral (including the Lightning Development Kit), and engaging in bitcoin policy advocacy through groups like COPA, the Digital Energy Council, the Crypto Council for Innovation, and the Texas Blockchain Council. The company also runs a significant open source program (contributing to projects like Goose, an on-machine AI developer agent, OkHttp, Retrofit, gRPC, Envoy, and MySQL) and an AI research effort, including co-founding the Agentic AI Foundation with Anthropic and OpenAI. Block serves individual consumers, small and medium-sized businesses/merchants, artists, and developers.
Skills
Candidate Availability
Required and preferred rules are kept separate and reflect the wording in the original posting.
About the Role
Join Block’s Risk Machine Learning organization to build end-to-end machine learning systems that detect, prevent, and reduce fraud and abuse across Cash App and Square. The role covers problem definition, modeling, deployment, monitoring, iteration, technical leadership, and production ML reliability.
Requirements
- 8+ years of industry experience in machine learning, applied AI, or related fields
- Bachelor’s degree in a quantitative field; Master’s or PhD preferred
- Experience independently designing, deploying, and maintaining ML solutions in production
- Familiarity with tree-based models, deep learning, transfer learning, or reinforcement learning
- Experience influencing technical direction and collaborating with cross-functional partners at scale
- Strong communication skills, sound judgment, and an ownership mindset
- Curiosity and alignment with Block’s mission of economic empowerment
Responsibilities
- Partner with product, engineering, data science, policy, and operations to design and productionize ML-driven risk solutions at scale
- Own end-to-end machine learning systems from problem definition and modeling through deployment, monitoring, and iteration
- Lead technical decision-making within workstreams and influence ML strategy and planning
- Build tooling and processes that improve the speed, reliability, and impact of the ML development lifecycle
- Apply advanced modeling techniques and third-party data sources to improve detection and decision-making
- Investigate emerging fraud, abuse, and risk patterns to inform product safeguards and policy
- Collaborate with ML platform and engineering teams to ensure models operate reliably in real time and at scale
Benefits
- Remote work
- Medical insurance
- Flexible time off
- Retirement savings plans
- Modern family planning
Hiring Process
Candidates may submit up to 9 active applications within a 60-day period. Reapplications to the same role are accepted 90 days after a previous application has been reviewed. Block may use automated AI tools to evaluate applications, subject to local regulations and bias audits.