Machine Learning Engineer

Location: Greater London

# Machine Learning Engineer Quantcast London  (Hybrid)
Full-timeAI tools:

Py Torch Upload  your resume once and Scout applies for you Apply with Scout Share this job:

Linked

InXSave image

The Machine Learning Engineer builds and maintains real-time machine learning systems that help Quantcast’s advertising platform evaluate and price advertising opportunities. The role combines experimentation and model development with production engineering, working alongside senior scientists and engineers.
* Permanent* Hybrid
* 0–2 years### Skills and expertise

Python Java Py Torch Scikit -learnXGBoost Pandas Num Py Distributed  systems### Key responsibilities
* Build and improve machine learning applications serving large volumes of real-time advertising requests.
* Run experiments to evaluate new modeling ideas and collaborate on model improvements.
* Optimize system performance and maintain clean, scalable production code.## How this job compares

Compared with 37 open junior machine learning jobs on October 10, 2026.Similar open jobs:
We Love AI Jobs lists 37 open junior machine learning jobs at 26 companies.

Remote work:
This job is hybrid. 0 of the 37 junior machine learning jobs (0%) are remote.

AI in this role:
High. AI is the core of the work: building, training or deploying AI systems. Building and experimenting with machine learning models and production systems is the core of the role. The posting describes models that predict user and advertising characteristics in real-time auctions.## Full description

At Quantcast, we don't just build advertising technology, we revolutionize how it works. Our AI-powered Demand Side Platform (DSP) connects the world's most ambitious marketers with their ideal audiences across the open internet, delivering results that actually move the needle. Since 2006, we've been the industry's trailblazer, launching the first AI-powered measurement platform for publishers and the first AI-driven DSP. Our AI doesn't just optimize—it delivers the measurable outcomes that matter most to our clients, giving them the competitive edge they need in a crowded marketplace.

Ready to join the team that's defining the future of digital advertising?

The Modeling team is responsible for Machine Learning (ML) systems  build and maintain high-frequency ML infrastructure that prices millions of advertising opportunities per second in a real-time auction environment to maximise advertiser outcomes. In less than 100 milliseconds, our models predict age, gender, viewability, fraud, advertiser relevance and many more characteristics of internet users. Using NLP, clustering and LLMs we build topics in multiple languages to help our advertisers target customers interested in their products.

As a Machine Learning Engineer you care about the health and maintainability of our systems and the velocity of the engineering teams. You explore data, research new algorithms, experiment with proof of concepts, and build out scalable real-time production systems to tackle challenges the company faces.

What you'll do:
• Design, code, test, and debug ML applications and constantly improve large-scale global systems that respond to millions of real-time requests per second, efficiently.
• Run Machine Learning experiments to test new modeling ideas.
• Collaborate with senior scientists and engineers to iterate on ML models and learn industry best practices for high-quality ML products and large-scale systems.
• Write clean, efficient, and maintainable code using industry best practices.
• Participate in code reviews and provide constructive feedback to team members.
• Identify performance bottlenecks and optimise system components for enhanced scalability.
• Keep up to date with developments in machine learning outside the…