Senior Machine Learning Engineer, Platform

Block is one company built from many blocks, all united by the same purpose: economic empowerment. We build technology that increases access and independence for sellers, individuals, and artists around the world. Working at Block means working on and across our brands—Square, Cash App, Afterpay, TIDAL, Spiral, and Proto— in roles that connect, enable, and push all of them forward faster.

We’re remote-first by design and operate with intelligence at the center of everything we do. At Block, you'll be challenged by some of the brightest, most creative minds in the industry and have the tools and autonomy to do the most meaningful work of your career.

The Role

Block’s Machine Learning (ML) Platform team builds shared infrastructure that helps teams develop, evaluate, deploy, and monitor models and automated decision systems for uses such as fraud detection, recommendations, and underwriting. You will work closely with applied machine learning teams across Block to shape our roadmap, improve established services, and build new platform capabilities. You will have opportunities to deepen your expertise across the ML lifecycle, influence system designs, and help other engineers grow through mentoring and design reviews.

You Will

• Design, build, and operate shared ML infrastructure, including feature stores, rules engines, model hosting and inference, training infrastructure, and offline model evaluation.
• Lead the design and delivery of large-scale distributed systems, balancing response time, throughput, data consistency, availability, and cost.
• Work with applied machine learning teams and internal customers to understand their challenges, identify common needs, and turn them into reusable platform capabilities; use that feedback to help set our roadmap and priorities.
• Build reliable services through automated testing, monitoring, capacity planning and safe deployments.
• Participate in the oncall rotation for mission-critical systems, lead incident response and reviews, and fix underlying causes to prevent repeat incidents and reduce manual support work.
• Build self-service interfaces, libraries, tools, and documentation that help teams develop models, move them into production, and understand how they perform.
• Mentor engineers, guide design reviews, and share practices that help the team build and maintain reliable systems.

You Have

• 8+ years of experience in software development and/or machine learning experience with a focus on internal platforms or infrastructure.
• Hands-on experience building and operating ML infrastructure, with depth in one or more areas such as feature stores, rules engines, model hosting and inference, or training infrastructure.
• Deep understanding of architectures for ML-backed solutions and the ML lifecycle - from data gathering, training, model evaluation, MLOps, and productionizing models (both classical ML and deep learning/LLMs).
• Experience designing and operating large-scale distributed systems, including understanding failure modes, maintaining correct data, and managing performance and capacity.
• Experience operating mission-critical services, including oncall, incident response, and improvements that made systems more reliable.
• Experience leading complex technical work from an unclear starting point through delivery: defining the problem, testing ideas, choosing a design, planning work with other teams, and checking the results.
• Experience working with teams that use your platform, explaining technical choices and trade-offs, and mentoring engineers.
• 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.
• Ruthless pragmatism when solving new and unconventional problems

Technologies We Use and Teach

• Kotlin / Java, Golang, Python, Typescript, React
• gRPC, Protocol Buffers
• AWS (Sagemaker, EC2, EKS, Dynamo), Databricks (Spark)
• NVidia Triton, vLLM, ONNX

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.