Machine Learning Engineer

Responsibilities About the team The USDS Platform and Community Integrity (PaCI) team is the architectural backbone of TikTok's Risk & Integrity in the US. We drive end-to-end integrity for TikTok 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 TikTok Live, Local Services, and User Growth. We architect the core ML infrastructure and risk intelligence that protect our billion-user ecosystem from adversarial threats. We are looking for talented individuals to join our team. As a graduate, you will get opportunities to pursue bold ideas, tackle complex challenges, and unlock limitless growth. Successful candidates must be able to commit to an onboarding date by the end of the year. Please state your availability and graduation date clearly in your resume. Candidates can apply to a maximum of two positions and will be considered for jobs in the order you apply. The application limit is applicable to our Company and its affiliates' jobs globally. Applications will be reviewed on a rolling basis - we encourage you to apply early. Global Ecosystem Governance: Lead the algorithmic architecture and governance for TikTok 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. Qualifications Minimum Qualification(s): Individuals who are completing or have recently completed a Bachelor's/ Master's degree in Computer Science, Engineering, Math, Statistics, or a related discipline. 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. Preferred Qualifications 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. Job Information The base salary range for this position in the selected city is $122574 - $187200 annually. Compensation may vary outside of this range depending on a number of factors, including a candidate’s qualifications, skills, competencies and experience, and location. Base pay is one part of the Total Package that is provided to compensate and recognize employees for their work, and this role may be eligible for additional discretionary bonuses/incentives, and restricted stock units. Benefits may vary depending on the nature of employment and the country work location. Employees have day one access to medical, dental, and vision insurance, a 401(k) savings plan with company match, paid parental leave, short-term and long-term disability coverage, life insurance, wellbeing benefits, among others. Employees also receive 10 paid holidays per year, 10 paid sick days per year and 17 days of Paid Personal Time (prorated upon hire with increasing accruals by tenure). The Company reserves the right to modify or change these benefits programs at any time, with or without notice. For Los Angeles County (unincorporated) Candidates 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: Interacting and occasionally having unsupervised contact with internal/external clients and/or colleagues; Appropriately handling and managing confidential information including proprietary and trade secret information and access to information technology systems; and Exercising sound judgment. About USDS TikTok 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 such, the company is shifting from a hybrid work model to a fully in-person schedule up to 5 days a week. Why Join Us Inspiring creativity is at the core of TikTok's mission. Our innovative product is built to help people authentically express themselves, discover and connect – and our global, diverse teams make that possible. Together, we create value for our communities, inspire creativity and bring joy - a mission we work towards every day. We strive to do great things with great people. We lead with curiosity, humility, and a desire to make impact in a rapidly growing tech company. Every challenge is an opportunity to learn and innovate as one team. We're resilient and embrace challenges as they come. By constantly iterating and fostering an "Always Day 1" mindset, we achieve meaningful breakthroughs for ourselves, our company, and our users. When we create and grow together, the possibilities are limitless. Join us. Diversity & Inclusion TikTok is committed to creating an inclusive space where employees are valued for their skills, experiences, and unique perspectives. Our platform connects people from across the globe and so does our workplace. At TikTok, our mission is to inspire creativity and bring joy. To achieve that goal, we are committed to celebrating our diverse voices and to creating an environment that reflects the many communities we reach. We are passionate about this and hope you are too. USDS Reasonable Accommodation USDS is committed to providing reasonable accommodations in our recruitment processes for candidates with disabilities, pregnancy, sincerely held religious beliefs or other reasons protected by applicable laws. If you need assistance or a reasonable accommodation, please reach out to us at #J-18808-Ljbffr