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# MODEL ENGINEER, POST-TRAINING & RL

- **Company:** Space X
- **Location:** United States
- **Salary:** $180,000.0
- **Contract:** Permanent contract
- **Skills:** Artificial Intelligence, C++ (Programming Language), Python (Programming Language), Machine Learning, Reinforcement Learning, Pytorch
- **Published:** November 1, 2026
- **Apply:** https://startup.jobs/model-engineer-post-training-rl-xai-7951036

## About the Role

* Experience writing production-quality code in Python, PyTorch, JAX, Rust, or C++, * You believe truth-seeking AI is the most important and challenging problem
 * You are obsessed about building incredibly useful models through post-training and RL techniques
 * You are a power user of AI models and eager to push the boundaries of what's possible with reinforcement learning and alignment methods
 * If you previously worked on post-training, RLHF, or trained models used by millions of people it's a big plus, but relevant experience is not required
 * You take pride in your work and thrive in meritocratic environments

## Description

You will work on the most critical post-training and reinforcement learning challenges at any given time - including reward modeling, preference optimization (RLHF/DPO), and RL for improving reasoning, truthfulness, and real-world capabilities.