JetBrains is a general software company that creates intelligent tools for software developers and teams. Since 2000, we have built products that help developers work more productively, write higher-quality code, and stay focused on solving real problems.
The JetBrains Research team is looking for a Senior Research Engineer to work on Code World Models: models that learn how software systems behave, change, execute, and interact with developer tools.
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.
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.
It Would Be a Plus If You
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

📌 Senior Research Engineer (España)
🏢 JetBrains
📍 España