Senior Model Engineer Reinforcement Learning Training Framework
SpaceXAI builds frontier AI models and products including the Grok conversational assistant and a multimodal developer API.
Funding history
About SpaceXAI
SpaceXAI is a US-based AI company focused on accelerating scientific discovery and understanding the universe through reasoning, voice, image, video, and generative AI systems. Formerly xAI, it was acquired by SpaceX effective February 2, 2026, while continuing to operate the x.ai site and services.
Skills
Candidate Availability
Required and preferred rules are kept separate and reflect the wording in the original posting.
About the Role
You will design and implement systems that support reinforcement-learning workloads, profile and debug end-to-end training performance, and improve the scalability and observability of the reinforcement-learning stack.
Requirements
- Production-quality programming in Python, PyTorch, JAX, Rust, or C++
- Experience training large models, including pre-training, post-training, fine-tuning, or reinforcement learning training of neural networks with more than 1 billion parameters
- Large-scale distributed systems
- Large-scale LLM training infrastructure
- Reinforcement learning numerics
- Reinforcement learning techniques
Responsibilities
- Design and implement systems that support reinforcement learning workloads from small ablations to production training runs
- Profile, debug, and optimize end-to-end training performance
- Improve the scalability and observability of the reinforcement learning stack
Benefits
- Equity
- Comprehensive medical coverage
- Vision coverage
- Dental coverage
- 401(k) retirement plan
- Short-term disability insurance
- Long-term disability insurance
- Life insurance
- Discounts and perks