AI Engineer & Researcher - Post-training

About the Role

The post-training team at xAI transforms powerful pre-trained models to become steerable, versatile, and capable of understanding and addressing real-world challenges.

As a post-training researcher/engineer, you will enhance the model's instruction-following capability and general usefulness to fulfill our mission – developing AI systems that can accurately understand the universe, create new knowledge, and improve themselves through interactions.

Focus

• Creating and driving research agenda to advance model quality.
• Improving data mixtures by building data collection pipelines and developing data generation techniques.
• Creating generalizable reward models and developing novel reinforcement learning algorithms.
• Designing and implementing robust model evaluations.
• Designing and implementing large-scale model training frameworks.
• Collaborating with pre-training, reasoning, data, multimodal, applied, product efforts to push the frontiers of model capability.

Ideal Experiences

• Expert in ML and fine-tuning large language models.
• Track record in leading research that significantly impacts AI advancement.
• Experience in data-driven large language model behavior improvements.
• Experience in advanced reinforcement learning or inference-time search techniques.
• Experience in developing benchmarks or large-scale distributed machine learning systems.
• Experience in model optimizations under complex setups (e.g., multi-modality, multi-context, multi-agent, long-horizon tasks, diverse user preference/feedback).

Location

The role is based in the Bay Area [San Francisco and Palo Alto]. Candidates are expected to be located near the Bay Area or open to relocation.

Tech Stack

• Python
• Jax
• Rust

Interview Process

After submitting your application, the team reviews your CV and statement of exceptional work. If your application passes this stage, you will be invited to a 15-minute interview (“phone interview”) during which a member of our team will ask some basic questions. If you clear the initial phone interview, you will enter the main process, which consists of four technical interviews:

1. Coding assessment in a language of your choice.
2. 2 x post-training technical sessions: These sessions will be testing your ability to formulate, design and solve concrete problems in post-training. It can be research or engineering, depending on background/experience. 
3. Meet the Team: Present your past exceptional work and your vision with xAI to a small audience.

Our goal is to finish the main process within one week. We don’t rely on recruiters for assessments. Every application is reviewed by a member of our technical team. All interviews will be conducted via Google Meet.

Annual Salary Range

$180,000 - $440,000 USD