Senior Machine Learning Engineer – Personalisation & Recommendations

Salary: £60,000 - 100,000 per year

Requirements

• We are looking for a seasoned Senior Machine Learning Engineer with a strong background in machine learning and production systems.
• We value experience in applied machine learning on real recommendations use cases, especially productionised sequential learning use cases.
• We value experience with ML and distributed ML frameworks such as Ray, Spark-MLlib, TensorFlow, and similar tools.
• We value experience with real-time scoring and evaluation of models under low-latency constraints.
• We value strong coding skills and software development experience; we use Spark, Python, and Java extensively.
• We value the ability to work with large-scale computing frameworks, data analysis systems, and modelling environments such as Spark, Hive, and NoSQL stores.
• We require a Bachelors, Masters, or PhD in Computer Science, Statistics, or a related field.
• An ad-tech or mar-tech background is a plus.

Responsibilities

• Apply data analysis and feature engineering expertise to identify and calculate features that can support multiple use cases and models.
• Train machine learning and statistical models, including recommendations, reinforcement learning, decision trees, Bayesian analysis, neural networks, and transformers, to address business use cases and improve product and system performance, quality, and accuracy.
• Build near real-time and batch inferencing services using infrastructure such as Spark and Ray that integrate with operational and analytics workloads.
• Help build a first-class machine learning platform from the ground up, supporting the full model lifecycle including feature engineering, training, evaluation, versioning, deployment, online serving, and monitoring prediction quality.
• Perform low-level systems debugging, performance measurement, and optimisation on large production clusters.

Technologies

• Hive
• Support
• Java
• Machine Learning
• Marketing
• NoSQL
• Python
• Roku
• Spark
• TensorFlow
• AI
• AI Agents
• Claude Code
• Cloud
• Cursor
• LESS
• MCP
• Model Training

More

We are Roku, the #1 TV streaming platform in the U.S., Canada, and Mexico, and we are on a mission to power every television in the world. We pioneered streaming to the TV and connect consumers, content publishers, and advertisers across the TV ecosystem. Our Advertising Engineering MarTech team builds products, services, and machine learning systems that deliver the right communication, creative, and marketing experience to the right customer at the right time. We are recruiting a Senior Machine Learning Engineer to help build intelligent systems that improve marketing effectiveness at scale. We offer a fast-paced, collaborative environment where everyone is focused on company success, and we generally work in the office Monday through Thursday with flexible remote Fridays for many roles. Our benefits include global mental health and financial wellness support, and local benefits may include healthcare, life, accident, disability, commuter, retirement, and paid time off, depending on location.

last updated 34 week of 2026