Senior Machine Learning Engineer, E-Commerce

ResponsibilitiesAbout the Team: Global E-commerce is a content-driven business powered by short-form video and live-streaming, dedicated to becoming the premier destination for users to discover affordable, high-quality products. Our team strives to deliver a tailored and efficient shopping experience while upholding a robust governance and risk control framework to ensure platform integrity, merchant compliance, and a secure ecosystem.

Responsibilities

• Architect and develop sophisticated LLM-based systems to process high-dimensional unstructured data (e.g., text, logs, conversations) from diverse sources.- Define and implement complex semantic understanding frameworks, including fine-grained intent classification and entity extraction, to achieve deep contextual awareness.- Apply state-of-the-art techniques to enhance model performance, including Instruction Tuning, RLHF/DPO, and Contextual Prompt Engineering.- Optimize model serving for production environments using quantization, distillation, and efficient attention mechanisms (e.g., FlashAttention, vLLM).Qualifications

Minimum Qualifications

• MS or PhD in Computer Science, AI, Mathematics, or a related field.- 5+ years of professional experience in one or more of the following fields: Machine Learning, Natural Language Processing (NLP), or Computer Vision.- Proficiency in software development with at least one of the following programming languages: C++, Python, Go, or Java.

Preferred Qualifications

• Experience in fine-tuning, distillation, or reinforcement learning for large language models in conversational AI applications.- Proficiency in multilingual NLP, machine translation, and cross-lingual dialogue modeling.- Experience in developing and optimizing e-commerce video and product multimodal large models, combining LLMs with video/product representations to support tasks like multimodal classification, video QA, and cross-modal retrieval.- A strong understanding of e-commerce policies, dispute resolution workflows, and merchant-buyer interactions to inform AI service design.About USDSTikTok 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 UsInspiring 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 AccommodationUSDS 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 https://tinyurl.com/USDS-RA​Job Information【For Pay Transparency】Compensation Description (Annually)The base salary range for this position in the selected city is $177688 - $341734 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:​1. Interacting and occasionally having unsupervised contact with internal/external clients and/or colleagues;​2. Appropriately handling and managing confidential information including proprietary and trade secret information and access to information technology systems; and​3. Exercising sound judgment.​