Software Engineer Intern (Recommendation Infra, Performance Efficiency) - 2027 Fall

About the Team The Recommendation System Infrastructure team is responsible for building and evolving the large-scale online serving and data infrastructure that powers TikTok’s recommendation products globally. Our mission is to deliver highly efficient, reliable, observable, and scalable infrastructure for recommendation systems. The team works closely with recommendation algorithm teams to accelerate strategy iteration, improve compute efficiency, optimize serving cost, and enable the next generation of AI-native and agentic engineering workflows. We focus on core infrastructure challenges across online/nearline/offline modules on GPU/CPU, high-performance computing, data pipelines, observability, automation, system reliability, and cost optimization. Our systems are primarily built in C++, while broader infrastructure and automation work may also involve offline data processing frameworks such as Flink, Spark, or other large-scale data systems. A key direction of the team is to build round-the-clock closed-loop agentic systems that can observe, diagnose, plan, execute, verify, and continuously improve recommendation infrastructure and iteration workflows. We are looking for talented individuals to join us for an internship. Our internship program offers students hands-on experience, industry exposure, and opportunities to apply their knowledge to real-world challenges while building a strong foundation for personal and professional growth. Interns will gain practical experience, explore potential career paths, and participate in social events, learning programs, and development workshops alongside industry professionals. Candidates may apply to a maximum of two positions across Our Company and its affiliates globally. Applications will be considered in the order they are submitted. Applications are reviewed on a rolling basis, so we encourage you to apply early. Please clearly state your availability in your resume, including your start and end dates. Candidates who pass resume screening will be invited to participate in Our Company's technical online assessment. Responsibilities - Design, build, and optimize high-performance online serving systems for large-scale global recommendation systems, improving business ROI, system efficiency, and serving quality. - Improve the efficiency, reliability, scalability, and cross-regional consistency of recommendation system infrastructure. - Identify and resolve system performance bottlenecks across CPU, memory, bandwidth, GPU compute efficiency, serving latency, throughput, and resource allocation efficiency. - Drive cost optimization for large-scale recommendation serving, including business-impact-based cost efficiency, compute resource utilization, and infrastructure-level or strategy-level performance improvements. - Build reliable and efficient workflows and pipelines for automation on candidate generation, profile generation, feature processing, training data generation, and online development. Minimum Qualification(s) - Currently pursuing a Bachelor's degree in Computer Science or a related technical discipline. - Strong programming skills in at least one systems programming language, such as C++, C, Go, or Java. - Experience in building scalable backend systems, distributed systems, infrastructure systems, or high-performance online services. - Solid understanding of data structures, algorithms, operating systems, networking, and distributed system fundamentals. - Experience with performance analysis, system debugging, reliability improvement, or large-scale service optimization. - Strong ownership, problem-solving ability, and communication skills. - Ability to work effectively with cross-functional teams, including infrastructure teams, recommendation algorithm teams, and product/business-facing engineering teams. Preferred Qualification(s) - Currently pursuing a Master's degree in Computer Science or a related technical discipline. - Experience with infrastructure for recommendation systems, search engines, advertising systems, machine learning systems, or large-scale online serving systems. - Experience optimizing high-throughput, low-latency C++ services in production environments. - Familiarity with profiling, benchmarking, performance tuning, capacity planning, resource efficiency improvement, and cost optimization. - Experience with large-scale data processing systems such as Flink, Spark, Kafka, or similar frameworks. - Experience building end-to-end automation systems based on AI agents, LLMs, workflow orchestration, or closed-loop engineering automation. - Experience designing agentic workflows for system diagnosis, performance optimization, reliability improvement, change validation, or automatic execution. - Experience with real-time data pipelines, online training, feature engineering, candidate generation, or recommendation system iteration workflows.