Senior Machine Learning Engineer for Search

How do you make our customers happy? With 13 million customers, 129 million monthly visits and about 41 million products on display, bol is the most successful online retail platform in The Netherlands and Belgium. And when we say ‘platform’, we mean it. Well over 49,000 external partners – and counting – enrich the product base. Data-driven, adventurous, we intend to deliver on our promise to make life easier and more fun for customers. And that is exactly what our IT 750+ professionals (25% internationals) do. Making mistakes is no biggie, as long as learnings are shared.

The biggest challenge Key challenges we are exploring include how to integrate complex machine learning models into a low-latency, high-traffic service without compromising performance or scalability. We are also focused on improving the feedback loop so that our algorithms can learn and adapt in near real time based on user interactions and changing conditions. Another area of interest is incorporating large language models (LLMs) into the search journey to enhance discovery, relevance, and user experience. Finally, we are investigating ways to identify and surface relevant products beyond traditional keyword matching, leveraging techniques such as embeddings and semantic search to better understand user intent and product relationships.

What you will do as Senior Machine Learning Engineer for Search As a Machine Learning Engineer, you’ll play a key role in designing, building, and deploying machine learning solutions that power bol.com’s data-driven innovations. Working in cross-functional teams alongside data scientists, software engineers, and business stakeholders, you’ll transform tested models into scalable, real-time production systems that directly enhance customer experiences.

We’re looking for an engineer who can bridge the gap between data science and software engineering—someone who can take ML concepts from idea to production using modern frameworks, MLOps best practices, and cloud technologies. You’ll tackle challenges like integrating low-latency models into high-traffic services, improving real-time feedback loops, and exploring LLM applications for search. Flexibility, curiosity, and a “get things done” mindset are essential as you balance rapid iteration with long-term scalability.

You bring:

• 5+ years’ experience as an ML Engineer, ideally in Search or Recommendations
• Strong Python, SQL, and data engineering skills (Airflow, DBT, Kubernetes, CI/CD)
• Experience deploying ML in production on cloud platforms (GCP preferred)
• Comfortable with agile workflows, A/B testing, and MLOps best practices

Why you can make a difference Your work will directly influence how millions of customers discover products every day. By turning advanced machine learning models into scalable, real-time search solutions, you will help make search more relevant, intuitive, and efficient. From implementing state-of-the-art retrieval techniques and LLM-powered experiences to improving feedback loops and production systems, your contributions will have a visible impact on both customer satisfaction and business outcomes.

Where you'll be working As a Machine Learning Engineer, you’ll be at the centre of our data intensive landscape. Our business model is focused on technology and data-driven improvements that drive innovation for our customers. The data science community in bol is a growing team of unique data savvy professionals consisting of Data Scientists, Machine Learning Engineers, Data Engineers and Software Engineers. Next to that there is also a specific MLE-community. The cross-functional teams, with ample representation from the business units, also give you a complete picture of the organization. Professional success in data science requires more than any university can teach you, and bol is the perfect place to learn the rest. The setting is informal, pragmatic and innovative. Our success is based on collaborating as equals and continuously learning from each other.

Something for you?

• Curious pragmatist: Yes, if you stay current with AI developments but always ask: "How does this solve a real problem?"
• Bridging the gap: Yes, if you like working on the overlap between AI, software, data engineering and data science
• Impact that can be seen: Yes, if you like real-time visible solutions in a high impact area of the company

Nothing for you?

• Certainty preferred: No, if something isn’t set in stone yet, you’ll wait for the ambiguity to dissipate
• Presumptuous: No, if you are the type that assumes to know our customers
• Single system specialist: No, if you prefer working on a single, well-defined system with clear specs and minimal cross-team coordination.

We take pride in our B Corp certification and strive for continuous improvement every day. Our annual bonus is tied to sustainability goals, and we are committed to equality and equal opportunities for all. Perks of having a blue heart

• 29 days: to recharge
• Travel costs: Public transport, car, parking & charging covered
• Pension plan: 75% premium covered
• Annual bonus: Based on sustainability goals