Senior Machine Learning Engineer - LLM Evaluation & Agent Systems

San Jose Regular R\&D Job ID: A129948 Responsibilities

About the Team

The TikTok U. S. Data Security (USDS) team is responsible for the security, integrity, and compliance of TikTok’s data within the United States.

The Data Platform Team builds a scalable, reliable, cost\-efficient infrastructure that ensures data integrity and empowers every business unit to win through self\-service tools and scientific insights.

About the Role

We are seeking a Senior Machine Learning Engineer to join our team as a technical lead, driving the architecture and execution of our next\-generation AI Risk \& Compliance Intelligence Platform and Intelligent Data Agent Ecosystem. In this role, you will be instrumental in bridging the gap between standard prompt engineering and native, model\-driven reasoning frameworks.

You will tackle complex ML challenges around offline/online evaluation, synthetic data generation for small\-sample scenarios, and automated agent skill optimizations across Data \& Engineering workflows (DA/DS/DE/SRE). Key Responsibilities \- Design, build, and scale robust LLM evaluation architecture, including automated offline datasets, metric suites, and benchmarking pipelines to measure prompt and model performance.

\- Innovate on LLM\-driven synthetic data generation methodologies to tackle data scarcity bottlenecks and systematically evaluate long\-tail/edge\-case risk scenarios. \- Advance beyond criteria\-based prompt engineering by extracting deep risk patterns directly from complex case data to build native, ML\-driven decision models and reasoning abstractions.

\- Architect, evaluate, and continuously optimize modular agent skills and tools tailored for Data Science, Analytics, Data Engineering, and SRE workflows to maximize tool\-use accuracy, execution efficiency, and task success rates. \- Implement advanced evaluation methodologies (such as LLM\-as\-a\-judge and multi\-agent benchmarking) across both risk intelligence and agentic ecosystems.

\- Provide technical leadership by establishing core ML system design patterns, benchmarking standards, and engineering best practices, while translating complex operational requirements into scalable machine learning solutions across cross\-functional partnerships.

Qualifications

• Minimum Qualifications \- Experience: 5\+ years of software/ML engineering experience with a strong track record of designing, building, and deploying ML/LLM systems in production.
• \- Generative AI \& LLMs: Deep hands\-on expertise with LLM architectures, fine\-tuning, RAG, prompt tuning, and agentic frameworks.
• \- Evaluation \& Data Bootstrapping: Demonstrated experience building robust LLM evaluation frameworks (LLM\-as\-a\-judge, automated benchmark pipelines) and tackling data scarcity/imbalance problems.
• \- Core Engineering: Strong coding skills alongside production experience with scalable data processing pipelines.
• Preferred Qualifications \- Prior domain experience in Risk \& Compliance Intelligence and Automated Decision Systems.
• \- Hands\-on experience with synthetic dataset generation or bootstrapping models for cold\-start scenarios.
• \- Experience building AI tools or agents for technical personas (Data Analysts, Data Scientists, Data Engineers, Data SRE).
• \- Demonstrated ability to serve as a founding technical lead on ambiguous, high\-impact initiative pods.
• Job Information 【For Pay Transparency】Compensation Description (Annually) The base salary range for this position in the selected city is $187040 \- $438000 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.

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 https://tinyurl. com/USDS\-RA