Research Engineer: Post-Training & RL for Specialized LMs

NextToken AI Inc.; Mountain View (CA); On-site; USD 180,000 - 240,000; Full time

Job summary

NextToken AI Inc. is hiring researchers and engineers to advance post-training methods for specialized language models and agents. You will design training recipes combining supervised fine-tuning, reinforcement learning, and distillation, and explore synthetic data generation for better signals.

You’ll work with founders, systems engineers, and customer teams to shape experiments, implement scalable evaluation tools, and document results for publication and open-source projects.

Qualifications

• Understanding of modern post-training methods like RL with verifiable rewards (RLVR).
• Depth in policy optimization (GRPO) or on-policy distillation (OPSD).
• Ability to reason about learning signals, tradeoffs, and failure modes.

Responsibilities

• Develop post-training methods for language models and agents.
• Design and run training recipes combining supervised fine-tuning, RL, and distillation.
• Investigate synthetic data generation and curation for learning signals.
• Build agent environments, reward models, and verifiers for training and evaluation.
• Collaborate with systems engineers to improve experiment and inference efficiency.
• Publish findings through technical writing and open-source contributions.

Skills

Experimental design

Communication of findings

Problem solving

Tools

PyTorch

JAX

Job description

NextToken AI Inc. is hiring researchers and engineers to advance post-training methods for specialized language models and agents. You will design training recipes combining supervised fine-tuning, reinforcement learning, and distillation, and explore synthetic data generation for better signals.

You’ll work with founders, systems engineers, and customer teams to shape experiments, implement scalable evaluation tools, and document results for publication and open-source projects.