Staff Machine Learning Engineer

Themis AI is building the next generation of uncertainty-aware AI infrastructure and tools to improve AI safety and reliability. Were looking for a Staff Machine Learning Engineer to lead the development of the high-performance libraries that form the foundation of our product offerings. This role is ideal for engineers who have deep experience building robust Python-based ML libraries and want to shape core systems that enable trustworthy AI deployments for novel and high-impact use cases. Full-Time | Location: Remote (U.S. time zones preferred) or Hybrid (Cambridge, MA) Core Responsibilities: Support the design, development, optimization and testing of our core ML libraries Collaborate closely with AI research teams to translate new innovations into high-performance, easy-to-use APIs and scalable systems Contribute to architectural decisions and long-term technical roadmaps Drive strong engineering practices: code reviews, automated testing, CI/CD, docs, etc. Mentor engineers and help maintain a culture of technical rigor and mission alignment Requirements: 5+ years of software engineering experience in Python and ML model development Deep understanding of machine learning fundamentals, particularly neural networks, optimization, probability theory, and linear algebra Strong software engineering practices: Git-based workflows, pull request reviews, testing infrastructure, release processes Major contributions to production-grade AI/ML frameworks, toolkits, or open-source tools Clear communicator with the ability to operate autonomously and prioritize effectively in a startup environment Experience working in high-performance, collaborative software teams Mission-driven mindset: you care deeply about building systems that matter Nice to Have: Experience in uncertainty quantification, Bayesian neural networks, probabilistic models Contributions to major ML or scientific computing libraries (e.g., PyTorch, NumPy, SciPy) Exposure to GPU programming, compiler-level optimization, and distributed systems At Themis, we believe that uncertainty is essential for building trustworthy, adaptive, and resilient AI. If you're excited about enabling the future of safe and efficient machine learning and building tools that top AI teams rely on, we want to hear from you. To apply, email us with the button below and include your resume, GitHub portfolio (if relevant), and a brief note explaining your interest in the role. #J-18808-Ljbffr