Machine Learning Engineer (AI Search), Tiktok Search

About TikTok TikTok is the leading destination for short-form mobile video. At TikTok, our mission is to inspire creativity and bring joy. TikTok's global headquarters are in Los Angeles and Singapore, and we also have offices in New York City, London, Dublin, Paris, Berlin, Dubai, Jakarta, Seoul, and Tokyo.​ 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.​ Job highlights Positive team atmosphere, Career growth opportunity, 100+ mil users, Meal allowance, Competitive compensation Responsibilities About the team Our Search Team focuses on LLM application algorithms for TikTok Search, with core scenarios including AI Search and TikTok AI Bot. We build search question-answer cards via LLM-powered generation and develop TikTok's official AI assistant, leveraging LLM ChatBot, Agent, and RAG technologies to deliver accurate, real-time responses. By closely integrating technical innovation with business scenarios, we bridge users with information and services, driving TikTok's business growth. Responsibilities: - Build AI Search Agents with planning, memory, and tool-use capabilities. Apply reinforcement learning, knowledge representation, and automated decision-making to solve complex problems end-to-end. - Enhance LLM-based query understanding: process multi-turn conversations, conduct semantic analysis on queries and documents, and ensure accurate, objective search results via LLM reasoning. - Optimize RAG and LLM pipelines: improve retrieval and ranking algorithms, train and optimize LLMs for answer generation (e.g., fine-tuning, inference optimization), and enhance the relevance and structured presentation of search results. - Translate research (e.g., Agent/LLM innovations) into production, collaborating with cross-functional teams to drive product upgrades. Qualifications Minimum Qualifications - Proficient in C++/Python; strong command of algorithms and data structures (e.g., retrieval, graph algorithms). - Basic understanding of LLM fundamentals (e.g., prompt engineering, fine-tuning workflows). - Strong problem-solving skills with a track record of delivering technical projects. Preferred Qualifications - Hands-on experience with LLM/Agent technologies: RAG optimization, RLHF/SFT for LLMs, or Agent framework development (e.g., planning/memory modules). - Excellent communication and collaboration skills, with a track record of exploring new technologies and driving technical advancements with teams.