Lead Machine Learning Engineer / Applied Scientist
$179,000–$302,500 year
Hybrid · Toronto, Ontario, Canada
Job Summary
Lead ML Engineer/Scientist to shape reinforcement learning systems powering Upwork’s Search & Recommendations and UMA AI assistant. Design and scale RL-based reasoning, planning, and retrieval architectures that connect research innovations to production outcomes. Mentor engineers, drive cross-functional efforts to deploy research prototypes into reliable production systems with strong performance, robustness, and observability. Collaborate with engineering, research, and Trust & Safety teams to improve explainability and risk mitigation; evaluate emerging RL/LLM techniques and translate promising innovations into practical applications for Upwork’s platform.
Required Qualifications
- Proven experience designing, training, and deploying reinforcement learning systems in production, with deep familiarity in planning methods such as Monte Carlo Tree Search and policy or value-based approaches.
- Strong expertise in machine learning systems that use vector databases, graph databases, knowledge graphs, or graph neural networks to improve reasoning and decision quality.
- Track record of leading technically complex initiatives across research and engineering partners, with the judgment to balance experimentation, scalability, and production reliability.
- Experience applying AI tools and iterative prompt or workflow strategies to accelerate model development, analysis, debugging, or experimentation while maintaining strong technical rigor.
- Passion for building intelligent agent systems that combine reinforcement learning, large language models, and retrieval techniques to solve meaningful product and platform challenges.
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