Machine Learning Developer

## About the Role JetBrains is looking for a **(Senior) Machine Learning Developer (Junie)** to help build and advance Junie, its AI coding agent available across JetBrains IDEs and as a standalone CLI. This role is focused on applying machine learning, large language models (LLMs), AI agents, and software engineering to rethink how software is developed. You will work across AI agent development, model optimization, autonomous coding workflows, and production software. The role offers end-to-end ownership, from early research and experimentation through production implementation, with a focus on improving Junie’s ability to handle complex engineering tasks autonomously. ## Key Responsibilities * Develop and ship new features for Junie across its standalone CLI and model integrations. * Experiment with model configurations, model ensembling, and cost-efficiency strategies. * Explore and develop autonomous AI agent behaviors for long-term software project maintenance. * Research, prototype, develop, test, and deliver production-ready machine learning and software capabilities. * Work on improving Junie’s ability to independently own, maintain, and evolve software subsystems over multi-day time horizons. * Optimize AI and LLM-based systems for an effective balance between cost and intelligence while maintaining code quality. * Take end-to-end ownership of technical initiatives, from initial research through production code. * Use Junie as part of your daily engineering workflow to continuously evaluate and improve its quality and user experience. * Explore new approaches to autonomous AI systems and AI-assisted software development. ## Required Qualifications * Proven track record of developing and shipping **machine learning or full-stack software products**. * Hands-on experience working with **large language models (LLMs), prompt engineering, or agentic AI workflows**. * Ability to write high-quality production code across the full software development lifecycle. * Practical experience building or fine-tuning machine learning models. ## Preferred Qualifications * Strong interest in autonomous AI systems and developer-focused software engineering tools. * Experience experimenting with emerging AI technologies and new approaches to software development. * Experience working on AI coding agents, autonomous agents, developer tools, or related software engineering technologies. * Experience with model optimization, model ensembling, or AI cost-efficiency strategies is relevant to the role. ## Skills & Competencies * Machine Learning * Large Language Models (LLMs) * Prompt Engineering * Agentic AI and Autonomous AI Systems * AI Coding Agents * Machine Learning Model Development and Fine-Tuning * Full-Stack Software Development * Production Software Engineering * CLI Tool Development * Model Integration * Model Ensembling * AI Model Optimization * Autonomous Coding Workflows * Software Engineering Tools * Research and Experimentation * End-to-End Technical Ownership * Rapid Learning and Adaptability * Problem Solving and Technical Curiosity * Long-Term Systems Thinking ## What Success Looks Like Success in this role means turning experiments in AI agent autonomy and cost efficiency into reliable, production-ready capabilities. Key outcomes include enabling Junie to handle increasingly complex, multi-day engineering tasks autonomously and continuously improving the engineering workflow through the AI coding tools you build and use. ## Work Arrangement & Locations The role is listed across the following locations: * Amsterdam, Netherlands * Belgrade, Serbia * Berlin, Germany * Limassol, Cyprus * London, United Kingdom * Madrid, Spain * Munich, Germany * Paphos, Cyprus * Prague, Czech Republic * Remote, Germany * Warsaw, Poland * Yerevan, Armenia The listing also states that JetBrains supports flexible work locations, including working from home or from an office, and allows up to **30 days per year of remote work from abroad**. JetBrains notes that many teams are distributed across its core locations and that relocation possibilities can be discussed for candidates who are not currently based in one of the listed locations. ## Compensation & Benefits * Strong base salary with competitive pay based on skills and experience. * Flexible work location with home or office options. * Up to 30 days per year working remotely from abroad. * Additional time off. * Medical insurance allowance for employees and their families. * Learning and development opportunities, including conferences, courses, and language classes. * Relocation support where relevant to the role. * Language classes for local languages or English. * Hot meals or a lunch allowance on workdays. * Professional mental health support. * On-site gym or sports club stipend. * Company-wide celebrations and team events. Benefits may vary depending on location. ## About JetBrains JetBrains creates intelligent software development tools for developers and teams. Its products are used by more than **15 million users** and more than **300,000 companies**, including 88 of the Fortune Global Top 100. The company focuses on improving developer productivity and supporting AI adoption at scale. ## Equal Opportunity JetBrains is an equal opportunity employer committed to an open and inclusive workplace. The company welcomes people regardless of background, identity, religion, age, accessibility needs, or orientation.