Moonlake
Member of Technical Staff — Agent Post-Training
San Francisco, CA · Staff · Full-time · Posted Jul 28, 2026
About the job
Build reinforcement learning infrastructure and post-training systems to improve multimodal, vision-language, and code-generating agents.
What you'll do
- Build RL and post-training pipelines, including infrastructure for fine-tuning, preference optimization, and reward modeling.
- Develop systems to collect and learn from agent trajectories, and create rewards, verifiers, and evaluations for long-horizon tasks.
- Scale distributed training and rollout generation while improving reliability, reproducibility, observability, and cost efficiency.
What they ask for
- Real-world experience training large language, vision-language, multimodal, or code models.
- Strong experience in reinforcement learning, post-training, or large-scale fine-tuning.
- Experience building distributed training or high-throughput inference systems.
- Strong Python skills and experience with PyTorch, JAX, or similar frameworks.
Nice to have
- Experience at a frontier AI lab or organization operating large-scale training systems.
- Experience with code-model post-training, autonomous coding agents, multimodal models, robotics, simulation, or embodied AI.
Tools
Python, PyTorch, JAX
AI focus
Train and post-train multimodal agents using supervised fine-tuning, preference optimization, reward modeling, and reinforcement learning; improve agents’ planning, coding, tool use, and performance on complex tasks, including robotics and embodied-model training.
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