# Senior Machine Learning Engineer (RecSys) at GRAI

> Open job at GRAI in Warsaw, Poland. Workplace: Hybrid.

Source: Poland Dev Jobs, https://poland-devjobs.com/jobs/grai-senior-machine-learning-engineer-recsys-cksbi8x
Posted 9 June 2026. Last checked on the employer's career site: 10 November 2026.

## Facts

- Company: [GRAI](https://poland-devjobs.com/companies/grai)
- Location: Warsaw, Poland
- Workplace: Hybrid
- Employment type: Full-time
- Polish: Not required
- Skills: PyTorch, Python, SQL, Spark, TensorFlow
- Not mentioned in the job post: salary, visa sponsorship, relocation, where you can apply from

## Job description

We are building an AI-powered music platform that’s transforming how people create, explore, and experience music. Our product leverages cutting-edge AI technologies to provide personalized music recommendations and unique features tailored to every music enthusiast.

As we continue to grow, we’re looking for a **Senior Machine Learning Engineer** to design, build, and scale recommendation systems that deliver highly relevant, personalized experiences to our users. You will work on large-scale user interaction data, develop retrieval and ranking models, and take them from experimentation to production.

### What You’ll Do

- Design and implement retrieval and ranking architectures for personalized recommendations
- Work with large-scale user behavior and content data to extract meaningful signals
- Build end-to-end ML systems: data processing, feature engineering, training, evaluation, deployment, monitoring
- Run A/B tests and offline evaluations to measure model impact and guide improvements
- Collaborate with product and engineering teams to align recommendations with business goals
- Continuously monitor model performance

### What We’re Looking For

- Strong hands-on experience building recommendation systems or ranking models
- Deep understanding of machine learning fundamentals and evaluation methodologies
- Experience working with large-scale data (SQL, Spark, or distributed data systems)
- Proficiency in Python and modern ML frameworks (PyTorch, TensorFlow)
- Understanding of core ML concepts: supervised/unsupervised learning, evaluation metrics, feature engineering
- Experience deploying ML models to production and maintaining them over time
- Ability to balance experimentation with production reliability

### Nice to Have

- Experience with real-time recommendation systems
- Knowledge of search / information retrieval systems
- Familiarity with feature stores, model monitoring, and ML infrastructure
- Experience in media, music, or consumer-facing personalization products

### Why Join Us

- Work on high-impact ML systems used by real users at scale
- Ownership over meaningful technical decisions, from modeling to production
- Collaborative, product-driven environment with strong engineering culture
- A supportive and dynamic startup culture where your ideas and contributions truly matter
- Opportunities for growth, learning, and shaping the future of our recommendation stack

## How to apply

Apply on the job page, https://poland-devjobs.com/jobs/grai-senior-machine-learning-engineer-recsys-cksbi8x: its Apply button opens the employer's own application page.

## More jobs from GRAI

- [Lead Machine Learning Engineer – Recommendation Systems](https://poland-devjobs.com/jobs/grai-lead-machine-learning-engineer-recommendation-systems-348ftc4): GRAI, Warsaw, Poland. Hybrid. Posted 1 July 2026.
- [Research Engineer](https://poland-devjobs.com/jobs/grai-research-engineer-52uhih3): GRAI, Warsaw, Poland. Hybrid. Posted 9 June 2026.