JetBrains

Senior Research Engineer (Code World Models)

📍 Amsterdam, Netherlands; Belgrade, Serbia; Berlin, Germany; Limassol, Cyprus; London, United Kingdom; Madrid, Spain; Munich, Germany; Paphos, Cyprus; Prague, Czech Republic; Warsaw, Poland; Yerevan, Armenia

Responsibilities

• Design and run pre-training, continued pre-training, and mid-training experiments for code models.
• Build and improve data pipelines for large-scale model training, including filtering, deduplication, mixture design, and dataset quality checks.
• Work with code corpora, repositories, tests, execution traces, and synthetic data.
• Develop evaluations for complex repository-level code reasoning tasks.
• Collaborate with researchers and engineers working on ML for code and AI developer tools.

Requirements

• Have hands-on experience with model pre-training, continued training, or mid-training.
• Have strong engineering skills in Python and experience with modern ML frameworks.
• Understand large-scale ML training workflows, including data processing, distributed training, checkpointing, evaluation, experiment tracking, and debugging.
• Have experience working with large datasets and care about data quality, contamination, sampling, and reproducibility.
• Have a background in NLP, ML for software engineering, or a similar domain.
• Enjoy working on research problems with high uncertainty and turning ideas into working experiments.

Nice-to-Haves

• Have experience training or adapting models for code generation, code understanding, software agents, program repair, test generation, or repository-level reasoning.
• Have worked with execution-based data, such as unit tests, traces, logs, compiler feedback, runtime states, or sandboxed code execution.
• Have experience with large-scale distributed training of models with 70B+ parameters.
• Understand evaluation challenges for code models, including benchmark contamination, flaky tests, execution-based scoring, and long-horizon task evaluation.
• Have contributed to ML infrastructure, open-source projects, or research systems.

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