Staff Research Engineer — Post-Training LLMs & Continual Learning

Trajectory; San Francisco (CA); On-site; USD 180,000 - 260,000; Full time

Job summary

Trajectory is hiring a Member of Technical Staff (Research) in San Francisco to design and build the post-training stack that enables models to continually learn from real production workflows. You will own end-to-end experiments across data, training, and evaluation, shaping telemetry into learnable signals and designing novel algorithms.

You will work with founders and design partners to influence technical and product decisions, contributing to the culture and architecture of a company

Qualifications

• 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 / research experience.

Responsibilities

• Design and build the post-training stack enabling continual learning from real production workflows.
• Own end-to-end experiments across data, training, and evaluation.

Skills

Experience training or serving LLMs

RL environments / evaluation suites

PyTorch / JAX / ML frameworks

Experimental design skills

Master’s / research experience

Education

Master’s / research experience

PhD (last year) in AI/RL

Tools

PyTorch

JAX

Job description

Trajectory is hiring a Member of Technical Staff (Research) in San Francisco to design and build the post-training stack that enables models to continually learn from real production workflows. You will own end-to-end experiments across data, training, and evaluation, shaping telemetry into learnable signals and designing novel algorithms.

You will work with founders and design partners to influence technical and product decisions, contributing to the culture and architecture of a company