Member of Technical Staff - Research Intern

Trajectory • San Francisco, CA

2d

About The Position

As a Member of Technical Staff (Research) at Trajectory, you will design and build the post-training stack that enables customers’ models to continually learn from real production workflows. You will own end-to-end experiments spanning data, training, and evaluation, including shaping telemetry into learnable signals, training and serving custom LLMs and agents, and designing novel algorithms. You will work directly with the founders and design partners, make foundational technical and product decisions, and help define the company’s culture and architecture.

Requirements

• Experience training or serving large language models.
• Experience building RL environments or evaluation suites for LLMs.
• Proficiency in PyTorch, JAX, or similar ML frameworks.
• Strong experimental design skills.
• Master’s degree or research experience.

Nice To Haves

• Background in pre-training or post-training RL for LLMs.
• Experience with high-performance computing or large-scale clusters.
• Contributions to open-source ML research or infrastructure.
• Demonstrated technical creativity through research, open-source contributions, or side projects.
• PhD candidate in the last year of the program, working on AI or RL open-source projects.

Responsibilities

• Design and build the post-training stack for continual learning from production workflows.
• Own end-to-end experiments across data, training, and evaluation.
• Shape telemetry into learnable signals.
• Train and serve custom LLMs and agents.
• Design novel algorithms.
• Work directly with founders and design partners.
• Make foundational technical and product decisions.
• Help define the company’s culture and architecture.

What This Job Offers

• Job Type: Full-time
• Career Level: Intern