Senior Machine Learning Data Processing Engineer in Berlin

Our client is a non-profit organisation advancing research and technical solutions for safe-by-design AI systems.

They are seeking a Senior ML Data Processing Developer to build, scale and optimise large-scale machine learning data pipelines. You will work across data engineering, data curation and machine learning, transforming web-scale data into high-quality datasets for next-generation AI models.

This role goes beyond traditional data engineering, with a strong focus on data quality, algorithmic filtering, model-based evaluation and novel data-processing techniques.

Key Responsibilities

• Design, build and scale end-to-end pipelines for web-scale ML training data.
• Develop data-processing systems for deduplication, quality scoring, filtering, toxicity removal, PII scrubbing, metadata extraction and custom transformations.
• Build data-quality tooling including heuristic filters, ML classifiers, LLM-based evaluators and human-in-the-loop workflows.
• Implement robust data versioning, lineage, provenance, monitoring and quality controls.
• Develop leakage-detection mechanisms to prevent evaluation contamination.
• Work with Research and Engineering teams to define evolving data requirements and identify large-scale datasets.
• Conduct dataset coverage analysis and develop targeted data-acquisition strategies.
• Collaborate with Legal and Governance teams on data licensing, compliance and privacy requirements.
• Build tools that enable researchers to efficiently explore and understand datasets.
• Improve the scalability, reliability, quality and cost-efficiency of data-processing workflows.

Requirements

• Degree in Computer Science, Software Engineering or a related field.
• 5+ years' experience in data processing, ML engineering or NLP.
• Experience working with massive unstructured text datasets at trillion-token scale.
• Strong experience with distributed processing frameworks such as Spark, Ray or Flink.
• Experience with PII scrubbing, content-safety filtering and evaluation-contamination prevention.
• Strong Python skills and experience writing production-grade data-processing systems.
• Experience with pipeline orchestration tools such as Airflow, Prefect or Dagster.
• Ability to collaborate across Research, Engineering and Legal/Governance teams.

Nice to Have

• Experience developing ML models for data-quality tasks, including classifiers and LLM-based evaluators.
• Familiarity with LLM inference optimisation tools such as vLLM or SGLang.
• Experience with Docker, Kubernetes and infrastructure-as-code.
• Familiarity with ML experiment tracking tools such as Weights & Biases.
• Experience with data licensing or web-scale data acquisition.
• Contributions to open-source data processing or NLP projects.

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