Member of Technical Staff - Research Intern
- Location
- San Francisco
- Work mode
- On-site
- Employment type
- Internship
Skills mentioned
- Training large language models
- Serving LLMs
- Reinforcement learning
- RL environment/evaluation design
- PyTorch
- JAX
- Experimental design
- High-performance computing
- Large-scale cluster experience
- Open-source ML contributions
- Research (Masters/PhD)
Picked out of the job description automatically; check the full description for what the employer asks for.
About the job
JOB DESCRIPTION
As a Member of Technical Staff (Research) at Trajectory, you will design and build the post‑training stack that lets our customers’ models continually learn from real production workflows. You will own end‑to‑end experiments across data, training, and evaluation: shaping telemetry into learnable signals, training and serving custom LLMs and agents, and designing novel algorithms. You’ll work directly with the founders and design partners, make foundational technical and product decisions, and help define both the culture and architecture of a company whose core mission is to enable continually learning intelligence.
REQUIRED 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
PREFERRED
- Background in pre- 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 (research, OSS, side projects)
- PhD (last year of PhD), working on AI / RL open source projects
ABOUT TRAJECTORY
Trajectory is a research and product lab creating the platform for continual learning.
AI is the most capable software ever built, and the least able to learn. Every valuable correction and edit that happens in a product evaporates at the next session. A few teams have closed this gap by hand-coupling their models to their products: Composer, Claude Code, Windsurf SWE-1.
Trajectory is the first scalable approach for every company: our platform unlocks the signal already sitting in product use, so companies can continuously post-train large-scale agentic models that outperform the frontier. Working with leading AI companies, including Decagon, Clay, Harvey, Mercor, and Rogo.
Founded by researchers from Deepmind, OpenAI, Meta, Apple, Amazon, and Scale. $15M led by Conviction, with Fei-Fei Li, Jeff Dean, and founders of Notion, Braintrust, Modal, Hugging Face, and Dropbox.
From Trajectory's careers page (Ashby), checked 5 Nov 2026.
How to apply
- Select Apply on trajectory.ai. It opens Trajectory's own application form in a new tab, run on Ashby.
- Fill in the form and upload your résumé there. Jobiwork never sees your application.
- Trajectory will reply to you directly. No real employer asks you for money to apply.
Posted 5 Nov 2026 · checked 5 Nov 2026 · Report this job