Anti-Cheat is Riot’s first defense against cheaters that don’t want to play fair. As a cross-discipline team of former cheaters, kernel developers, machine learning engineers, data analysts, and software engineers, they make products like Vanguard to detect and ban the bad guys across all of Riot’s competitive titles and platforms, staying vigilant to whatever shape they’ll take in response. From beaming bots to scorching scripters, anti-cheat enables Riot’s game teams to take on competitive genres and design rewarding systems that would otherwise be too vulnerable to fraudsters and cheaters. Riot Machine Learning Engineers on Anti-Cheat are builders, trailblazers, and stewards of competitive integrity. We protect the legitimacy of Riot’s multiplayer games and player experience by building automated detection and decisioning systems to address a wide range of anticompetitive threats. As a Staff Applied AI/ML Scientist on Anti-Cheat, you will build machine learning driven detection systems to identify players engaging in cheating and other forms of abuse, and will develop agentic systems for reviewing and and actioning these players. You will partner with anti-cheat experts as well as game product, engineering, and insights teams to ensure that all Riot games afford safe, fair environments for players to compete and thrive. You will report to the Senior Manager of Anti-Cheat Data and Analytics.

Responsibilities:

• Design, train, and deploy real-time machine learning models to detect gameplay anomalies, automated bots, and memory-tampering exploits.
• Build scalable inference pipelines capable of evaluating millions of high-throughput game actions per second with minimal latency impact.
• Partner with anti-cheat software engineers to identify emerging cheat techniques and engineer high-signal features from raw game client telemetry.
• Establish robust ML Ops practices, including automated model retrain loops and continuous monitoring for adversarial drift.
• Analyze complex, high-dimensional player data to minimize false positives and maintain a fair, competitive environment for players globally.
• Work directly with game design and gameplay engineering teams to balance strict anti-cheat enforcement with smooth, responsive, and uninterrupted player experiences.
• Collaborate with the data engineering team to troubleshoot and optimize ETL pipelines, ensuring efficient data flow and processing.
• Help set technical direction within Anti-Cheat ML in an ever-evolving anti-cheat landscape

Required Qualifications:

• Bachelor’s degree or higher in Computer Science, Machine Learning, Statistics, or a related quantitative field, or equivalent practical experience.
• 6+ years of experience delivering ML systems in production, including 3+ years in applied modeling or ML research roles.
• Deep understanding of traditional machine learning models, and production deployment experience in at least one domain: computer vision, graph neural networks, transformer architectures, or agentic systems. 
• Excellent written and verbal communication with both technical and nontechnical stakeholders.
• Demonstrated history of quickly delivering impactful machine learning solutions for critical business problems 
• Product owner's mindset, to be able to identify opportunities for impact and then see them through to production.
• Track record mentoring engineers across roles and levels; evidence of raising the bar for people around you.

Desired Qualifications

• Experience working in adversarial detection (e.g. information/cyber security, fraud, money laundering, cheating, etc).
• Familiarity with relational databases (e.g., MySQL, Postgres), document stores (e.g., ElasticSearch), and distributed storage systems (e.g., HDFS, S3, Google Cloud Storage).
• Experience defining telemetry or instrumentation needs in close partnership with software or data engineers.
• Working understanding of Windows internal mechanics (e.g. processor memory, driver architecture, etc.) and how adversarial software can leverage them to bypass security controls.
• Understanding of high-performance competitive multiplayer games and the challenges associated with them.

For this role, you'll find success through craft expertise, a collaborative spirit, and decision-making that prioritizes the delight of players. We will be looking at your past studies, experience, and your personal relationship with games. If you embody player empathy and care about players' experiences, this could be your role!

Our Perks:

Riot focuses on work/life balance, shown by our open paid time off policy and other perks such as flexible work schedules. We offer medical, dental, and life insurance, parental leave for you, your spouse/domestic partner, and children, and a 401k with company match. Check out our benefits pages for more information.

At Riot Games, we put players first. That mission drives every decision in our quest to create games and experiences that make it better to be a player. Whether you’re working directly on a new player-facing experience or you’re supporting the company as a whole, everyone at Riot is part of our mission. And just like in our games, we’re better when we work together. Our goal is to create collaborative teams where you are empowered to bring your unique perspective everyday. If that sounds like the kind of place you want to work, we’re looking forward to your application.

It’s our policy to provide equal employment opportunity for all applicants and members of Riot Games, Inc. Riot Games makes reasonable accommodations for handicapped and disabled Rioters and does not unlawfully discriminate on the basis of race, color, religion, sex, sexual orientation, gender identity or expression, national origin, age, handicap, veteran status, marital status, criminal history, or any other category protected by applicable federal and state law. We consider for employment all qualified applicants, including those with criminal histories, in a manner consistent with applicable federal, state and local law, including the California Fair Chance Act, the City of Los Angeles Fair Chance Initiative for Hiring Ordinance, the Los Angeles County Fair Chance Ordinance for Employers, the San Francisco Fair Chance Ordinance, and the Washington Fair Chance Act.

Per the Los Angeles County Fair Chance Ordinance, the following core duties may create a basis for disqualifying candidates with relevant criminal histories:

• Safeguarding confidential and sensitive Company data
• Communication with others, including Rioters and third parties such as vendors, and/or players, including minors
• Accessing Company assets, secure digital systems, and networks
• Ensuring a safe interactive environment for players and other Rioters

These duties are directly related to essential operations, safety, trust, and compliance obligations within our organization. Please note that job duties may evolve based on business needs and additional responsibilities may be assigned as necessary to maintain operational efficiency and security.