Senior Machine Learning Engineer, AI​/ML Platform

Senior Machine Learning Engineer, AI/ML Platform

Remote Bay Area, CA, US

Posted Date: 10/30/25

Block is one company built from many blocks, all united by the same purpose of economic empowerment. The blocks that form our foundational teams — People, Finance, Counsel, Hardware, Information Security, Platform Infrastructure Engineering, and more — provide support and guidance at the corporate level. They work across business groups and around the globe, spanning time zones and disciplines to develop inclusive People policies, forecast finances, give legal counsel, safeguard systems, nurture new initiatives, and more.

Every challenge creates possibilities, and we need different perspectives to see them all. Bring yours to Block.

Block uses Machine Learning and AI across many of its products and domains. For ML practitioners Block-wide, the ML Inference & Training team provides critical infrastructure, platforms, and libraries required to develop, product ionize, and observe ML models.

We are an established team of 13 engineers and 1 manager across a few countries and timezones, sitting within the ML & Data Platform organization. Our projects cover extending mature platforms (e.g online ML hosting/inference, internal python SDKs) as well as greenfield initiatives such as LLM hosting/monitoring, rearchitecting our training stack, or building out new tooling for large-scale offline evaluations.

We are looking for an enthusiastic and experienced Machine Learning Engineer to join our team and help us build out the best ML infrastructure possible. In this role, you'll work closely with applied ML teams across Block to understand their challenges - scoping and exploring opportunities to improve their ability to deliver novel ML solutions at scale.

You'll work on high-visibility, meaningful projects that can have a significant impact on Block's continued success with ML, influencing our roadmap and working across the ML Lifecycle. We welcome individuals who are passionate about building for the real world, embracing pragmatic approaches, and seeing challenges from fresh, nontraditional viewpoints.

• Develop scalable ML/AI systems and platforms
• Be on the cutting edge of advancements in ML/AI across the industry
• Collaborate across diverse teams to deliver impactful platform solutions by understanding and generalizing the problems of cross-functional stakeholders
• Support critical ML systems used for fraud detection, language models, recommendation systems and underwriting
• Influence our roadmap and ensure we're working on the highest impact problems within the ML infrastructure domain

• 8+ years of experience in software development and/or machine learning experience with a focus on internal platforms or infrastructure
• Deep understanding of architectures for ML-backed solutions and the ML lifecycle - from data gathering, training, model evaluation, MLOps, and product ionizing models (both classical ML and deep learning/LLMs)
• A desire to understand our clients' needs in order to design tools and systems that solve our customer's problems. As a platform team, our main customers are internal developers and products
• Ability to produce production-quality code and services incorporating testing, evaluation, monitoring 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

We value general and versatile engineering skill over specific experience with our current stack, but some examples:

• Golang, Python, Type Script, React
• AWS (Sagemaker, EC2, EKS), Databricks
• 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…