Machine Learning Engineer, AI Search - USDS

Responsibilities

About the Team

The Search team is responsible for the machine learning algorithm for TikTok's rapidly growing video search, ecommerce search, local service search and AI search business. We use state-of-the-art large-scale machine learning technology, cutting-edge NLP, CV and multi-modal technology and generative models (LLM, VLM) to build the industry's search engines to provide the best search experience, for more than 1 billion monthly TikTok users around the world.

About the Role

TikTok is seeking an independent developer for the Search team. This role is pivotal in advancing TikTok's search capabilities by integrating cutting-edge recommendation algorithms and large language models (LLMs) technologies to deliver highly personalized and engaging user experiences.

Responsibilities

• Independent execution: Independent development, experiment, analysis and deployment of large-scale personalized search and recommendation systems, ensuring scalability, efficiency, and robustness.
• LLM Integration: Research and integrate LLMs within the recommendation pipeline to enhance content understanding, user intent recognition, personalization and content generation. Explore hybrid models that combine LLMs with traditional recommendation systems to mitigate feedback loops and uncover novel user interests.
• Innovation with Generative Recommendation Systems: Drive the integration of generative recommendation approaches, leveraging generative models to directly generate personalized content recommendations, moving beyond traditional ranking-based methods. This includes exploring frameworks like GenRec, which utilize LLMs/VLMs to interpret user contexts and generate relevant recommendations.
• Cross-functional Collaboration: Work closely with product managers, data scientists, infrastructure engineers, operation teams to enable search personalization strategies with overall product goals.

Qualifications

Minimum Qualifications:

• Educational Background: Bachelor's or advanced degree in Computer Science, Machine Learning, or a related field.
• Technical Expertise: Proficient in machine learning frameworks (e.g., TensorFlow, PyTorch), programming languages (e.g., Python, Java, C++), and deep understanding of data structures and algorithms.
• Industry experience: 2+ years in developing large-scale search or recommendation systems (feed, search, advertisement, etc). Familiarity with generative recommendation frameworks and their application in large-scale systems is highly desirable.
• LLM experience: Hands-on experience with deploying and improving LLMs for real-world applications, including techniques like prompt engineering, supervised fine tuning, reinforcement learning, and retrieval-augmented generation.

Preferred Qualifications

• Global Experience: Experience working with international teams and understanding of diverse user behaviors across different regions.
• Open Source Contributions: Active participation in open-source projects related to search, recommendation, or NLP.
• Publications: Contributions to conferences such as NeurIPS, ICML, ACL, or RecSys are a plus.

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 u