Senior Machine Learning Engineer - Remote in Cambridge

Roku is changing how the world watches TVRoku is the #1 TV streaming platform in the U.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.Canada, and Mexico with 70+ million active accounts. Roku enables our users to access millions of pieces of content — movies, episodes, news, sports, music, and channels — from all around the world, and our advertising systems connect advertisers to that audience at scale.You’ll join Praveen Krishnaiah’s Native Ads Modelling team building the ML systems behind ad relevance, bid and yield optimization, and real-time, low-latency ad serving. This is a senior, hands-on ML engineering role spanning modelling, large-scale training, and production infrastructure — you’ll take models from idea through to serving at scale, working in Spark, Python, and Java. You’ll work closely with Praveen and the wider Ad Performance ML team. 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 you have built fluency across the agentic engineering toolchain — coding harnesses like Claude Code or Cursor, MCP servers, custom skills, or agent frameworks — and 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.Design, train, and ship ML models for ad relevance and bid/yield optimizationBuild and maintain production ML infrastructure for real-time, low-latency servingWork across Spark, Python, and Java to move models from research to productionApply sound feature engineering, validation, and evaluation practices throughout the modelling lifecycleDiagnose production ML issues such as model drift or long-tail classification problemsCommunicate technical trade-offs clearly to engineering and cross-functional partnersWhat experience would help someone be successful in this role at Roku?Senior-level ML engineering experience, ideally with exposure to ad tech, recommendation, or auction systemsStrong grounding in ML fundamentals, feature engineering, and model evaluationExperience with Spark, Python, and Java in production ML settingsComfort with production ML infrastructure and real-time, low-latency serving requirementsDemonstrated AI/agentic-tooling fluency per the section aboveClear communicator who can explain reasoning and trade-offs, not just conclusions#LI-MS3What'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.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. AccommodationsRoku 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.That penchant for action gives us a pragmatic approach to innovation, one that has served us well since 2002.