xAI
Model Engineer, RL Training Framework
$180K–$440K
Palo Alto, CA · Full-time · Posted Jul 14, 2026
About the job
Develops and improves the reinforcement learning training framework and infrastructure, from small experiments to production training runs.
What you'll do
- Design and implement systems for RL workloads.
- Profile, debug, and optimize end-to-end training performance.
- Improve scalability and observability of the RL stack.
What they ask for
- Experience writing production-quality code in Python, PyTorch, JAX, Rust, or C++.
Nice to have
- Experience building, debugging, and optimizing large-scale distributed systems or LLM training infrastructure.
- Knowledge of reinforcement learning techniques or RL numerics; ability to work across unfamiliar areas of the stack.
Pay
$180,000 - $440,000 USD (base salary)
Tools
Python, PyTorch, JAX, Rust, C++
AI focus
Develops infrastructure for reinforcement learning training workloads.
Model-written summary · the original posting is authoritative