Senior AI Model Engineer — Scale & Train Large Models

SpaceXSI; Palo Alto (CA); On-site; USD 180,000 - 440,000; Full time

Benefits offered by this job

Equity

Medical, Vision, and Dental benefits

401(k) retirement plan

Disability insurance

Job summary

SpaceXSI is building the next generation of Super Intelligence to help humanity understand the universe. Our teams are creating a full stack—from Colossus supercomputers to Grok models and applications like Grok Bot and Grok Imagine—aimed at powering more capable AI systems.

As part of our engineering team, you will scale synthetic data to trillions of tokens, distill model intelligence into compact flash models, optimize mid-training data mixtures, and design robust evaluation for mid-training

Qualifications

• Experience writing production-quality code in Python, PyTorch, JAX, Rust, or C++.
• Experience training large models (e.g., pre-training, post-training, fine-tuning, or RL training of neural networks with 1B+ parameters).

Responsibilities

• Scale synthetic coding data to trillions of tokens with large-scale docker verification
• Distill the intelligence of flagship models into flash models through synthetic data generation
• Optimize mid-training data mixtures to boost the ceiling for RL
• Develop robust and diverse evaluation for mid-training checkpoints

Skills

Python

PyTorch

JAX

Rust

C++

Production-quality code

Tools

Spark

Ray

Job description

SpaceXSI is building the next generation of Super Intelligence to help humanity understand the universe. Our teams are creating a full stack—from Colossus supercomputers to Grok models and applications like Grok Bot and Grok Imagine—aimed at powering more capable AI systems.

As part of our engineering team, you will scale synthetic data to trillions of tokens, distill model intelligence into compact flash models, optimize mid-training data mixtures, and design robust evaluation for mid-training