Machine Learning Engineer, TikTok Risk & Integrity - USDS

The USDS Platform and Community Integrity (PaCI) team is the architectural backbone of Tik Tok’s Risk & Integrity in the US. We drive end-to-end integrity for Tik Tok and its expanding ecosystem, including Lemon8 and emerging affiliate platforms, by leveraging localized US data and state‑of‑the‑art AI/LLM capabilities.

Our mission is to deliver AI‑driven algorithmic solutions that detect and neutralize systemic threats across critical domains: from Account Integrity, Feed, and Social to Tik Tok Live, Local Services, and User Growth. We architect the core ML infrastructure and risk intelligence that protect our billion‑user ecosystem from adversarial threats.

• Global Ecosystem Governance:
  Lead the algorithmic architecture and governance for Tik Tok US across key domains, including account integrity, incentive abuse, content safety, and financial risk, ensuring a fair and secure ecosystem for a billion‑user community.
• Universal Representation Modeling:
  Build high‑precision, risk representation models leveraging massive heterogeneous data (video, live streams, audio, behavior sequences, and social graphs) to enable cross‑scenario risk perception.
• Dynamic Adversarial Defense:
  Research and counter global adversarial threats (e.g., large‑scale automated attacks, AIGC harmful content). Architect self‑evolving defense systems that maintain robustness and resilience against rapid tactic shifts and data drift.
• Intelligent Decision‑making:
  Drive the integration of Generative AI and Multimodal technologies into the risk lifecycle. Leverage LLMs and deep learning models to solve complex adjudication and interpretability challenges, balancing precision with automated, large‑scale enforcement.

• Bachelor’s degree or higher in Computer Science, Mathematics, Statistics, or a related field.
• Solid foundation in Machine Learning; proficient in applying Transformer and GNN architectures to solve large‑scale integrity challenges with social graph and behavior sequence data. Experience designing model evaluation systems that balance technical performance with product goals.
• Strong engineering and coding skills. Proficient in at least one language among Python, C++, or Go; familiar with distributed computing (e.g., Spark, Flink) and deep learning frameworks (e.g., PyTorch).
• A passion for building world‑class risk infrastructure and the ability to communicate effectively in a global, cross‑cultural environment.

• Agentic AI
  
  Experience:
  
  Hands‑on experience building LLM‑based Agents capable of task planning, tool‑use, or closed‑loop autonomous decision‑making.
• LLM Security & Alignment:
  Experience in LLM Post‑training or Fine‑tuning (e.g., SFT, RLVR, RLHF) to optimize models for specific risk domains like fraud intent recognition or malicious redirection.
• Multimodal Expertise:
  Proven track record in video understanding or multimodal representation; ability to integrate visual, audio, and textual features to solve complex behavioral modeling challenges.
• Industry Vision:
  Experience in Integrity, Anti‑Abuse, Safety, or Trustworthy AI at a large‑scale internet platform.

Tik Tok USDS Joint Venture LLC is dedicated to the safety and security of millions of Americans who create, discover, and connect with what they love on the apps we operate. The Joint Venture has been established in compliance with the Executive Order signed by President Trump on September 25, 2025. Our foundation is a comprehensive data privacy and cybersecurity program we operate under defined safeguards to protect national security and secure U.S. user data, apps and the algorithm.

We safeguard the U.S. content ecosystem, holding decision‑making authority for trust and safety policies and moderation. USDS Joint Venture helps ensure Americans can continue to express their creativity, discover new hobbies and interests, and build thriving communities and businesses on a global scale.

On‑site presence across teams allows the company to operate with greater speed, alignment, and agility — especially in areas like real‑time decision‑making, team development, and integrated execution. As…