Senior Lead Machine Learning Engineer, Agentic AI at Upwork

This role is designed for a seasoned expert in Machine Learning—specifically someone with 8–12+ years of experience who has moved beyond basic LLM implementation into the world of **Agentic AI**. You are an ideal candidate if you possess a deep understanding of multi-agent systems, tool-use, and the infrastructure required to make these systems reliable at scale. You should be equally comfortable fine-tuning models (SFT, RLHF) as you are architecting low-latency backend services. The standout aspect of this position is the chance to lead the "next generation" of intelligence for a global marketplace. It’s a high-impact, hands-on leadership role where you will build the platform that powers agents for both internal teams and external developers. Note that this role is **on-site in Toronto** and will initially be managed through a hiring partner while the local hub is established. **You might be a good fit if you:** * Have successfully shipped production-grade agentic workflows (planning, memory, reflection) to real users. * Are an expert in Python and have deep experience with LLM adaptation, including function calling and safety guardrails. * Can build evaluation harnesses to measure complex metrics like hallucination rates and task completion. * Enjoy mentoring senior engineers and influencing technical roadmaps across an entire organization.