Houyi Li 李厚意

AI Infrastructure Lead & Principal Engineer · TikTok

Former Pretraining Lead & Senior Researcher · StepFun

LLM/VLM pretraining · Scaling laws · Model architecture & model-system co-design · AI infrastructure (inference and distributed training)

At TikTok, I lead an AI Infrastructure team and have systematically strengthened its organization and engineering capabilities. I led an inference architecture overhaul that substantially improved production efficiency, and unified TikTok’s post-training frameworks. Our systems support training and inference for over a thousand LLMs and VLMs, handling TikTok’s massive real-world production traffic. I also explore agentic engineering and recursive self-improvement (RSI) for AI infrastructure, alongside team and engineering development.

Previously, I founded and led StepFun’s pretraining team, reporting to Xiangyu Zhang. I led pretraining and model architecture design for Step3, with hands-on responsibility spanning training data, core training code, and the main training runs. I also led Step2-mini end to end, from pretraining through post-training and deployment, and contributed to Step3.5-Flash’s architecture. My research included the Predictable Scale series—Step Law and Farseer—on hyperparameter scaling and predicting large-model performance. Alongside these papers, we open-sourced thousands of research models to support reproducible pretraining research.

Prior to StepFun, I was the LLM Lead at Alibaba International in 2023, reporting to Kaifu Zhang. I managed the full model lifecycle, from pre-training and post-training to driving the core LLM technology for commercial initiatives such as Aidge . I led the team that delivered multilingual large models Marco-7B and Marco-13B, and pioneered their path to commercial viability.

My earlier experience at Taobao and Kuaishou focused on personalized recommendation and advertising. I specialized in deploying deep learning at scale in consumer-facing (ToC) products to drive measurable business impact and boost profitability. In the same timeframe, I developed the classic personalized retrieval algorithm PDN (paper).

After graduating from Xidian University, I began my career in Ant Group's Infrastructure(Infra) team, where I spent four years with a focus on AI Infra. A key achievement from this period was developing the distributed training framework GraphTheta from scratch, one of the early frameworks in China to support thousand-machine parallel training.

Open source models and news

✦ Our paper “Can Mixture-of-Experts Surpass Dense LLMs Under Strictly Equal Resources?” was accepted as an ICLR 2026 Oral. I gave the oral presentation in Brazil on April 25, 2026. Camera ready / Poster / Slides
Predictable Scale: Part II, Farseer: A Refined Scaling Law in Large Language Models was accepted as a NeurIPS 2025 Spotlight. Camera ready / Poster
Step3 (321B-A38B) was open-sourced. It is designed end-to-end to minimize decoding costs while delivering top-tier performance in vision–language reasoning.
We open-sourced more than 400 language models for scaling-law research, covering models with up to approximately 10 billion parameters and training runs with up to approximately 100 billion tokens.
We released nearly 4,000 research models spanning a wide range of hyperparameter configurations to support reproducible LLM pretraining research.

Selected publications

01

Can Mixture-of-Experts Surpass Dense LLMs Under Strictly Equal Resources?

Houyi Li*, Ka Man Lo*, Ziqi Wang, Zili Wang, Wenzhen Zheng, Shuigeng Zhou, Xiangyu Zhang, Daxin Jiang
ICLR 2026 Oral (* = Equal Contribution)
02

Predictable Scale: Part II, Farseer: A Refined Scaling Law in Large Language Models

Houyi Li*, Wenzhen Zheng*, Qiufeng Wang, Zhenyu Ding, Haoying Wang, Zili Wang, Shijie Xuyang, Ning Ding, Shuigeng Zhou, Xiangyu Zhang, Daxin Jiang
NeurIPS 2025 Spotlight (* = Equal Contribution)
03

Predictable Scale: Part I, Step Law -- Optimal Hyperparameter Scaling Law in Large Language Model Pretraining

Houyi Li*, Wenzhen Zheng*, Qiufeng Wang, Hanshan Zhang, Zili Wang, Shijie Xuyang, Yuantao Fan, Zhenyu Ding, Haoying Wang, Ning Ding, Shuigeng Zhou, Xiangyu Zhang, Daxin Jiang
04

Step-3 is Large yet Affordable: Model-system Co-design for Cost-effective Decoding

The StepFun Team (Houyi Li: Core Model Architecture Contributor) (Technical Report)
05

Multi-matrix Factorization Attention

Jingcheng Hu*, Houyi Li*, Yinmin Zhang, Zili Wang, Shuigeng Zhou, Xiangyu Zhang, Heung-Yeung Shum, Daxin Jiang
ACL 2025 (* = Equal Contribution)
06

Path-based Deep Network for Candidate Item Matching in Recommenders

Houyi Li, Zhihong Chen, Chenliang Li, Rong Xiao, Hongbo Deng, Peng Zhang, Yongchao Liu, Haihong Tang
07

GraphTheta: A Distributed Graph Neural Network Learning System With Flexible Training Strategy

Yongchao Liu*, Houyi Li*, Guowei Zhang, Xintan Zeng, Yongyong Li, Bin Huang, Peng Zhang, Zhao Li, Xiaowei Zhu, Changhua He, Wenguang Chen
(* = Equal Contribution)
Alibaba Group logo
Alibaba Group 2016 - 2021 & 2023 - 2024
Kuaishou Group logo
Kuaishou Group 2021 - 2023
StepFun logo
StepFun 2024 - 2025
TikTok 2026 - Present
Full-resolution portrait of Houyi Li (李厚意)