Senior Machine Learning Engineer – Personalisation & Recommendations

TEAMWORK MAKES THE STREAM WORK.   ROKU IS CHANGING HOW THE WORLD WATCHES TV Roku is the #1 TV streaming platform in the U.S., Canada, and Mexico, and we've set our sights on powering every television in the world. Roku pioneered streaming to the TV. Our mission is to be the TV streaming platform that connects the entire TV ecosystem. We connect consumers to the content they love, enable content publishers to build and monetize large audiences, and provide advertisers unique capabilities to engage consumers. From your first day at Roku, you'll make a valuable - and valued - contribution. We're a fast-growing public company where no one is a bystander. We offer you the opportunity to delight millions of TV streamers around the world while gaining meaningful experience across a variety of disciplines.   WHAT DOES THE TEAM WORK ON?  Roku pioneered TV streaming and continues to innovate and lead the industry. The Roku Channel has us well-positioned to help shape the future of streaming. Continued success relies on building customer relationships with Roku that delight and engage them. Within Advertising Engineering, the MarTech team builds the products, services, and machine learning systems that help Roku deliver the right communication, creative, and marketing experience to the right customer at the right time on the right marketing channel. The team is focused on turning data, experimentation, and intelligent decisioning into production systems that improve marketing effectiveness at scale. Our mission is to build cutting-edge advertising technology and marketing products to support and grow a sustainable advertising business. The team owns server technologies, data platforms, and cloud services that power advertising and marketing use cases. We are recruiting a Senior Machine Learning Engineer to build and enhance intelligent systems that help the marketing team harness the power of data.   WHAT IS THE ROLE?  The MarTech team at Roku is looking for a seasoned Senior Machine Learning Engineer with a strong background in machine learning and production systems. This role sits in a team working on high-impact problems across marketing and advertising, where machine learning is being applied to improve customer decisioning, creative and campaign performance, and the systems that support experimentation and optimisation. Examples of such problems include creative personalisation for customers, improving ad relevance and targeting, inferring demographics, yield optimisation, and many more. Employees in this role are expected to apply knowledge of experimental methodologies, statistics, recommendations, reinforcement learning, optimisation, probability theory, and machine learning, using code for statistical analysis and tool building, using both general-purpose software and statistical languages. The ideal candidate will have endless curiosity and can pair a global mindset with locally relevant execution. You should be a gritty problem solver and self-starter who can work effectively with engineering, product, data science, and commercial stakeholders across Roku. The successful candidate will display a balance of hard and soft skills, including the ability to respond quickly to changing business needs.   HOW WILL I USE AI AT ROKU?  At Roku, we don’t just use AI, we work with it. AI agents and smart tools help power drafts, analysis, and repetitive workflows, while our people bring direction, judgment, and accountability. We’re looking for curious, adaptable builders who can show how they’ve used AI or automation to move faster, raise the bar, and scale their impact.   We value your AI skills if have built fluency across the agentic engineering toolchain — coding harnesses like Claude Code or Cursor, MCP servers, custom skills, or agent frameworks. And you can describe projects where you shipped real work with these tools. You know how to drive an agent, verify its output, and ramp on an unfamiliar codebase with an agent helping you.   WHAT ARE THE RESPONSIBLITIES OF THE ROLE?  • Data Analysis / Feature Engineering: Apply your expertise to identify and calculate features that can be leveraged by multiple use cases as well as models. • Train Machine Learning Models: Use machine learning and statistical modelling techniques such as recommendations, reinforcement learning, decision trees, Bayesian analysis, neural networks and transformers to develop and evaluate algorithms to address business use cases and/or to improve product/system performance, quality and accuracy. • Near Real-Time and Batch Inferencing: Use infrastructure like Spark and Ray to stand up inferencing services that integrate with operational/analytics workloads. • ML Infrastructure: Help build a first-class machine learning platform from the ground up which helps manage the entire model lifecycle: feature engineering, model training/evaluation, versioning, deployment/online serving and monitoring prediction quality. • Low-Level Systems Debugging, Performance Measurement & Optimisation: Performance measurement and optimisation on large production clusters. WHAT EXPERIENCE WOULD HELP SOMEONE BE SUCCESSFUL IN THIS ROLE AT ROKU?  • First-hand experience in applied machine learning on real recommendations use cases (brownie points for productionised sequential learning use cases!). • Experience with ML/distributed ML frameworks like Ray, Spark-MLlib, TensorFlow etc. • Experience with real-time scoring/evaluation of models with low latency constraints. • Great coding skills and strong software development experience (we use Spark, Python and Java a lot). • Ability to work with large-scale computing frameworks, data analysis systems and modelling environments. Examples include technologies like Spark, Hive, NoSQL stores etc. • Bachelor’s, Master’s or PhD in Computer Science, Statistics or a related field. • Ad-tech/Mar-tech background is a plus. #LI-PA1 WHAT'S ROKU'S APPROACH TO HYBRID WORKING? Roku fosters an inclusive and collaborative environment where teams generally work in the office Monday through Thursday. Fridays are generally flexible for remote work, except for employees whose specific roles or assigned office location require five days' a week attendance.   WHAT ARE SOME OF THE BENEFITS? Roku is committed to offering a diverse range of benefits as part of our compensation package to support our employees and their families. Our comprehensive benefits include global access to mental health and financial wellness support and resources. Local benefits include statutory and voluntary benefits which may include healthcare (medical, dental, and vision), life, accident, disability, commuter, and retirement options (401(k)/pension). Employees are supported in taking time off, in accordance with local leave policies and other personal needs to support their evolving work and life needs. It's important to note that not every benefit is available in all locations or for every role. For details specific to your location, please consult with your recruiter.   ACCOMMODATIONS Roku welcomes applicants of all backgrounds and provides reasonable accommodations and adjustments in accordance with applicable law. If you require reasonable accommodation at any point in the hiring process, please direct your inquiries to EmployeeRelations@Roku.com [employeerelations@roku.com?subject=Job%20Application%20Accommodations].   WHAT SHOULD I KNOW ABOUT ROKU'S CULTURE? Roku is a great place for people who want to work in a fast-paced environment where everyone is focused on the company's success rather than their own. We try to surround ourselves with people who are great at their jobs, who are easy to work with, and who keep their egos in check. We appreciate a sense of humor. We believe a fewer number of very talented folks can do more for less cost than a larger number of less talented teams. We're independent thinkers with big ideas who act boldly, move fast and accomplish extraordinary things through collaboration and trust. In short, at Roku you'll be part of a company that's changing how the world watches TV.  We have a unique culture that we are proud of. We think of ourselves primarily as problem-solvers, which itself is a two-part idea. We come up with the solution, but the solution isn't real until it is built and delivered to the customer. That penchant for action gives us a pragmatic approach to innovation, one that has served us well since 20 02.  To learn more about Roku, our global footprint, and how we've grown, visit https://www.weareroku.com/factsheet [https://www.weareroku.com/factsheet]. By providing your information, you acknowledge that you want Roku to contact you about job roles, that you have read Roku's Applicant Privacy Notice [https://www.weareroku.com/roku-job-applicant-privacy-notice-for-job-applicants], and understand that Roku will use your information as described in that notice. If you do not wish to receive any communications from Roku regarding this role or similar roles in the future, you may unsubscribe at any time by emailing WorkforcePrivacy@Roku.com [workforceprivacy@roku.com?subject=Unsubscribe%20Request%20].