LLM Post-training Engineer Intern (Research & Product) - 2027 Summer San Jose Undergraduate​/Mas

Location:

San Jose

Intern

A08601A

About the team

The Multimedia AI team at Tik Tok focuses on building, researching, and applying Large Language Models (LLMs) to power our global products. We believe the most impactful problems in AI arise at the intersection of research and real-world deployment—and post-training is where that intersection is sharpest.

We are looking for talented individuals to join us for an internship. Our internship program offers students hands‑on experience, industry exposure, and opportunities to apply their knowledge to real‑world challenges while building a strong foundation for personal and professional growth.

Interns will gain practical experience, explore potential career paths, and participate in social events, learning programs, and development workshops alongside industry professionals.

• 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.

• Currently pursuing an Undergraduate or Master’s degree in Computer Science, Machine Learning, or a related technical discipline.
• Strong programming skills in Python and experience with deep learning frameworks such as PyTorch or JAX.
• Foundational understanding of Transformer architectures and LLM training principles.
• Demonstrated ability to learn quickly in a fast‑paced environment and a strong passion for AI "landing" and product application.

• Previous experience or research projects involving LLM fine‑tuning, RLHF, or synthetic data generation.
• Familiarity with distributed training tools (e.g., Deep Speed, Megatron‑LM).
• Experience or interest in multimodal AI (integrating text with video or audio).
• Proven track record of building and deploying AI projects, either through previous internships, open‑source contributions, or academic research.

The hourly rate range for this position in the selected city is $45- $45.

Benefits may vary depending on the nature of employment and the country work location.

• Interns have day one access to health insurance, life insurance, wellbeing benefits and more.
• Interns also receive 10 paid holidays per year and paid sick time (56 hours if hired in first half of year, 40 if hired in second half of year).
• Interns who are not working 100% remote may also be eligible for housing allowance.

The Company reserves the right to modify or change these benefits programs at any time, with or without notice.

Qualified applicants with arrest or conviction records will be considered for employment in accordance with all federal, state, and local laws including the Los Angeles County Fair Chance Ordinance for Employers and the California Fair Chance Act. Our company believes that criminal history may have a direct, adverse and negative relationship on the following job duties, potentially resulting in the withdrawal of the conditional offer of employment:

Tik Tok is the leading destination for short‑form mobile video. At Tik Tok, our mission is to inspire creativity and bring joy. Tik Tok's global headquarters are in Los Angeles and Singapore, and we also have offices in New York City, London, Dublin, Paris, Berlin, Dubai, Jakarta, Seoul, and Tokyo.