Senior AI/LLM Engineer

We are looking for an experienced AI Engineer to join the Creator ML team.

We apply state of the art Machine Learning to optimize all possible aspects of the construction and serving of our banners. In this role, you will work across the full lifecycle of large language model applications: from dataset creation and evaluation to agent APIs, observability, and production-grade LLM features.

More broadly, within the Creator group, we are on a mission to revolutionize the creative capabilities offered to our clients across our commerce media platform. You will play a crucial role in shaping the landscape of Internet advertising, and you will have the opportunity to work on projects that impact billions of users worldwide.

Your main missions

• Develop LLM-powered features which include optimizing prompts, model selection, and inference strategies for quality, latency, and cost. You will be implementing end-to-end observability capabilities and agent executions. As well, you will have the opportunity to shape the development of infrastructure for Agents and MCP-based agent interfaces to support Agentic Creative workflows.
• Ensure systems are robust, testable, and reproducible. You will be contributing to internal tooling for experimentation, evaluation, and monitoring of Large Language Models.
• Challenge the status quo of our creative tooling for creation and optimization by leveraging more recent advancements in Generative AI. You will as well partner closely with product managers and designers to define AI-powered features, user flows, and success metrics
• In a multi-cultural team of 6, you will be collaborating closely with your mentor to drive your project, design and ensure best practices are applied. You can ask questions and participate in all knowledge-sharing sessions/workshops, etc. You are encouraged to actively voice your ideas whilst learning how to build and ship quality solutions code into production which will affect millions of users instantly.

• You have a master's degree/PhD in Machine Learning, Computer Science or a related quantitative field.
• You have experience in development in at least one mainstream programming language (Python, Java, C++, C#, etc.).
• You have hands-on experience building applications with LLMs, experience with APIs, distributed systems and/or ML platforms.
• Familiarity with LLM evaluation methods and dataset construction.
• Good understanding of observability concepts (logging, tracing, metrics)

It would be nice if you:

• Have experience with agent frameworks, MCP or tool calling protocols.
• Experience running LLM systems in production.
• Knowledge of cost optimization and latency tuning for LLM inference.

We acknowledge that many candidates may not meet every single role requirement listed above. If your experience looks a little different from our requirements, but you believe that you can still bring value to the role, we'd love to see your application

We acknowledge that many candidates may not meet every single role requirement listed above. If your experience looks a little different from our requirements but you believe that you can still bring value to the role, we'd love to see your application

Criteo is a leader in commerce media, helping brands, agencies, and publishers create meaningful consumer connections through AI-powered advertising solutions. We're shaping a more open and sustainable digital future for advertising.

At Criteo, our culture is as unique as it is diverse. From our offices across the globe or from the comfort of home, our 3,600 Criteos collaborate together to build an open, impactful, and forward-thinking environment.

We foster a workplace where everyone is valued, and employment decisions are based solely on skills, qualifications, and business needs—never on non-job-related factors or legally protected characteristics.

Ways of working – Our hybrid model blends home with in-office experiences, making space for both.

Grow with us – Learning, mentorship & career development programs.

Your wellbeing matters – Health benefits, wellness perks & mental health support.

A team that cares – Diverse, inclusive, and globally connected.

Fair pay & perks – Attractive salary, with performance-based rewards and family-friendly policies, plus the potential for equity depending on role and level.

Additional benefits may vary depending on the country where you work and the nature of your employment with Criteo.