ML Engineer

About Piano 

Piano helps the world's leading digital businesses grow revenue by understanding and influencing customer behavior. Our platform unifies analytics, audience segmentation, and commercial personalization in one AI-driven system, enabling media companies and digital services to maximize the value of every user interaction. Headquartered in Amsterdam with offices across the Americas, Europe, and Asia-Pacific, Piano serves hundreds of global brands including the BBC, Deutsche Telekom, Nikkei, and the Wall Street Journal. 

At Piano, engineers and data scientists tackle complex technical challenges at scale, from globally distributed systems and real-time machine learning models to production LLM applications that are transforming how our customers work. We embrace a culture of innovation, collaboration, and craftsmanship where you'll solve meaningful problems that impact millions of users worldwide. 

The Role 

We're looking for an ML Engineer to join our Data Science team and help maintain, extend, and evolve the machine learning models that power Piano's products for some of the world's biggest media brands. You'll work on real production systems serving hundreds of millions of users — primarily focused on keeping our existing ML solutions healthy and effective, with opportunities to contribute to new LLM-powered features along the way. 
 
We're looking for someone who combines strong engineering instincts with genuine curiosity about data and how ML systems behave in the real world. You're comfortable navigating unfamiliar codebases, you ask sharp questions, and you find real satisfaction in shipping solutions that are reliable, maintainable, and make a meaningful difference for the people using them. 

What You’ll Do 

• Maintain and improve existing ML pipelines, model training workflows, and inference services to keep them stable and performant 

• Investigate and resolve production issues when they arise — understanding the problem by analyzing logs, model inputs and outputs, identifying root causes, and shipping enhancements that continuously improve how our ML systems perform 

• Contribute to new ML/AI features 

• Collaborate with data scientists, ML engineers, product managers, and other teams across the company to deliver ML solutions that solve real customer problems 

• Write clean, tested, well-documented Python code and uphold good engineering practices (Git workflows, code reviews, CI/CD) 

You Might Enjoy This Role If You 

• Are comfortable navigating unfamiliar codebases and quickly building a mental model of how systems work 

• Have strong data intuition and enjoy hands-on exploratory data analysis to uncover patterns, anomalies, and insights in complex datasets 

• Are curious about data quality, evaluation, and how ML/AI systems behave in the real world 

• Care about building ML systems that perform well and earn trust in production 

• Are excited to grow into a strong applied ML engineer 

What We're Looking For 

Must-have 

• B.Sc. or M.Sc. in Computer Science, Mathematics, Statistics, Data Science, or a related field 

• 2+ years of professional experience as an ML Engineer, Data Scientist, or in a similar applied ML role 

• Deep understanding of core ML concepts (algorithms, evaluation, model behavior) 

• Strong Python skills and proven experience writing production-quality code  

• Experience with Git and modern collaborative development workflows  

• Strong analytical and debugging skills with a structured approach to problem-solving 

• Hands-on experience with coding agents such as Claude Code 

• Clear communication in English 

Nice-to-have 

• Experience with LLMs (OpenAI, Anthropic, or similar APIs) 

• Experience with Docker, Kubernetes, cloud platforms (AWS/GCP), CI/CD, and observability tooling (logging, metrics, monitoring) 

• Experience with ML pipeline tooling (Airflow or similar)  

• Experience with SQL and working with large datasets 

• Exposure to A/B testing infrastructure for ML models 
  

Why Piano 

• Your work will directly shape how leading global brands serve their audiences 

• You'll have real influence over the solutions you build and the tools you use 

• You'll collaborate with skilled peers across data science, ML engineering, and product 

• You'll get broad exposure — from classical ML to cutting-edge LLM applications 

• Generous token usage budgets with a focus on getting value from coding agents 

• Flexible working hours, competitive compensation, and benefits 

• Laptop of your choice (Windows/Mac) 

• Modern office with dedicated seating 

Applicants must have authorization to work in this jurisdiction without sponsorship from Piano.