Senior Software Engineer - Ads Optimization

Teamwork makes the stream work. Roku is changing how the world watches TVRoku 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 is the No. 1 TV streaming platform in the US, Canada and Mexico, with more than 100 million active accounts. Every ad impression across that platform has to be cleared and priced in real time — that is what the Ads Auctions and Marketplace Optimization team does. We build the auction mechanics, the pricing and pacing logic, and the low-latency systems that run them, balancing outcomes for advertisers, publishers, viewers, and Roku on every request. We are growing the team in Cambridge, which is becoming its largest hub, alongside colleagues in Amsterdam, Austin, San Jose, Ukraine and Uruguay — so you would be shaping how the UK side of this team works rather than inheriting it. What is the role? You will build the systems that apply mathematical and algorithmic rigour to optimise across multiple objectives, deciding which ads get served, in which placements, and when. The work spans auction mechanics, optimisation, the output of predictive ML models, and the real-time infrastructure underneath, mostly in Java on the JVM. It is hands-on and senior in scope: expect to move between whiteboard-level design and production code in the same week, and to own problems from framing through rollout. You will work directly with the hiring manager and a small group of senior engineers, in codebases shared with other ads engineers, on problems where your decisions are visible in revenue. You will optimise for second-order effects in a marketplace where participants react to each other, and to us, in real time. We are looking for people who are enthusiastic about solving these kinds of problems. 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 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 responsibilities of the role? Design and build components of Roku's real-time ad auction and marketplace systemsOwn the multi-objective optimisation at the core of the auction, balancing what advertisers, publishers, viewers, and Roku each want from the same impressionOwn development work end to end, from framing the problem through production rolloutBuild and operate JVM services where latency and reliability are product requirements, not stretch goalsUse probability, statistics and experimentation to test changes before and after launchWork with AI tooling as a normal part of how you design, build, test and reviewExplain technical trade-offs clearly to engineering and cross-functional partnersWhat experience would help someone be successful in this role at Roku? Around six or more years building production software, with strong systems judgementProduction experience in Java or another JVM language, or depth in a comparable statically typed language such as C#, C++ or Go, and the appetite to ramp on JavaComfort designing and operating distributed systems at scale and low latencyA solid grounding in maths, algorithms, probability and statistics as applied to real systemsDemonstrated AI and agentic-tooling fluency, as described aboveAd tech, auctions or marketplace experience is preferred, and we move quickly for candidates who have itComparable experience on mathematically rigorous or optimisation-heavy problems in another domain is an acceptable alternative 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. 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. 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 2002.  To learn more about Roku, our global footprint, and how we've grown, visit 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, 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.