Member of Technical Staff - Post-Training

Reflection

93d

About The Position

Build systems that transform powerful pre-trained models into aligned and general agents. Drive research and engineering initiatives that push the frontier of post-training, from data curation to large-scale optimization. Develop data generation pipelines, reward models, reinforcement learning algorithms, and inference-time scaling techniques. Collaborate across pre-training and post-training teams to deliver step-function gains in model capability. Contribute to shaping our understanding of how large models learn to reason, follow instructions, and improve through reinforcement learning.

Requirements

• Deep understanding of machine learning fundamentals and practical experience with large-scale LLM training.
• Strong engineering skills, comfortable diving into complex ML codebases and distributed systems.
• Experience improving model behavior through data, reward modeling, or RL techniques.
• Evidence of owning ambitious research or engineering agendas that led to measurable model improvements.
• Thrive in a fast-paced, high-agency startup environment; bias toward action and clarity of execution.
• Able to work fluidly across research and infra boundaries.
• Strong communication capabilities and comfort working collaboratively.
• Passionate about advancing the frontier of intelligence.

Responsibilities

• Build systems that transform powerful pre-trained models into aligned and general agents.
• Drive research and engineering initiatives that push the frontier of post-training.
• Develop data generation pipelines, reward models, reinforcement learning algorithms, and inference-time scaling techniques.
• Collaborate across pre-training and post-training teams to deliver step-function gains in model capability.
• Contribute to shaping our understanding of how large models learn to reason, follow instructions, and improve through reinforcement learning.

Benefits

• Top-tier compensation: Salary and equity structured to recognize and retain the best talent globally.
• Comprehensive medical, dental, vision, life, and disability insurance.
• Fully paid parental leave for all new parents, including adoptive and surrogate journeys.
• Financial support for family planning.
• Paid time off when you need it.
• Wellness and time-saver stipend.
• Commute benefits.
• Education stipend.
• Relocation support.
• Lunch and dinner provided daily.
• Regular off-sites and team celebrations.

What This Job Offers