Member of Technical Staff - Post-Training (Reinforcement Learning & Generalization)

Remote · New York · Toronto · Full-time · Remote · Posted Oct 14, 2026

At a glance

As a Member of Technical Staff in Post-Training, you will train large language models using reinforcement learning and develop methods that help them generalize beyond their training distribution.
You will design training recipes, environments, and evaluations to determine true skill acquisition versus task fitting, turning successful research into production models.

Design, run, and analyse large-scale RL post-training experiments (e.g., RLHF, RL from verifiable rewards).
Research and develop methods that improve out-of-distribution generalization, such as reward design, environment and task diversity, curricula, and regularization.
Build held-out evaluations that measure generalization to unseen tasks, domains, and formats, and that catch reward hacking and benchmark overfitting.
Diagnose training dynamics and failure modes, including instability, reward over-optimization, and capability regressions.
Turn successful research into robust, reproducible training recipes for production models.

Strong research and software engineering skills, with hands-on experience training LLMs.
Experience applying reinforcement learning to LLMs (e.g., PPO, GRPO, RLHF, RLVR), ideally at scale.
Track record of work on generalization, robustness, or distribution shift, through publications or shipped models.
Rigorous experimental practice: clean ablations, careful controls, and sound conclusions from noisy results.
Excellent communication skills.
Deep understanding of data quality principles and best practices: demonstrates willingness to dive deep into data while possessing strong intuition for assessing the quality of datasets and anticipating how different data characteristics will impact model training outcomes.

Experience with distributed training (e.g., JAX, PyTorch, FSDP, Megatron) is a plus.

A weekly lunch stipend of $75/£75 or equivalent in your local currency for lunch.
Full health and dental benefits, including a separate budget for mental health.
RRSP matching, 401K, Pension Scheme.
100% Parental Leave top-up for up to 6 months, for either parent.
Annual enrichment benefits including arts & culture, fitness/wellness, quality time, and a workspace improvement credit.
Education & learning stipend for conferences, courses, and coaching.
6 weeks of paid vacation (30 working days!)
Budget for traveling to other offices if you are remote, plus an annual company offsite.
Co-working benefit for those not near an office.
$500 home office stipend to set up your workspace properly.

This role can be based remotely or from one of the office locations listed on the job description.
There is no minimum in-office qualification requirement.