LLM Post-training Engineer Intern (Research & Product) - 2027 Summer

TikTok is a short-form mobile video platform whose Multimedia AI team builds and applies Large Language Models to support global products. The intern will support LLM post-training, evaluation, reward modeling, alignment research, dataset analysis, and the transition of research into production AI applications.

Responsibilities:

• Support the development and optimization of post-training strategies, including instruction tuning, preference tuning (SFT/DPO/PPO), and model alignment
• Assist in building robust evaluation pipelines to measure model performance, helpfulness, and safety across diverse multimedia product use cases
• Participate in the research and implementation of cutting-edge methodologies in reward modeling and human preference learning
• Collaborate with engineering teams to bridge the gap between experimental research and production-ready AI applications (e.g., video understanding, translation, and content classification)
• Analyze and process large-scale datasets to identify patterns that improve model behavior and alignment quality