Lead ML Engineer - Music Recs & Real-Time Personalization

GRAI Inc.; Poland; On-site; PLN 320,000 - 460,000; Full time

Benefits offered by this job

Founding-stage equity

Paid time off (26 days)

Job summary

GRAI Inc. in Warsaw, currently in alpha, is seeking a Lead Machine Learning Engineer to architect and scale our recommendation and discovery engines. You will own the technical roadmap for the RecSys stack and turn raw behavior signals into personalized, real-time experiences.

You will lead a team of ML engineers, design end-to-end ML infrastructure, and drive data-driven evaluation while collaborating closely with Product and Engineering to achieve business goals.

Qualifications

• Extensive experience designing production-grade recommendation systems, search engines, or large-scale ranking models.
• Deep knowledge of machine learning, deep learning architectures, and retrieval methodologies.
• Experience with distributed data systems and modern ML frameworks (PyTorch, TensorFlow).
• Background in deploying and maintaining low-latency models in production, with feature stores and drift monitoring.
• Demonstrated leadership in technical projects and mentoring engineers.
• Ability to balance advanced AI experimentation with production stability and business value.

Responsibilities

• Define the long-term technical vision and roadmap for RecSys and personalization engines.
• Design scalable retrieval, ranking, and re-ranking pipelines for massive datasets.
• Build and own ML infrastructure: data processing, feature stores, and real-time monitoring.
• Mentor ML engineers and foster a culture of excellence and experimentation.
• Design offline evaluation and lead A/B testing to iterate on model performance.
• Collaborate with Product and Engineering to align ML with business metrics.

Skills

Machine Learning

Team Leadership

MLOps

System Design

Data Analysis

Cross-functional Collaboration

Tools

PyTorch

TensorFlow

Airflow

Spark

Job description

GRAI Inc. in Warsaw, currently in alpha, is seeking a Lead Machine Learning Engineer to architect and scale our recommendation and discovery engines. You will own the technical roadmap for the RecSys stack and turn raw behavior signals into personalized, real-time experiences.

You will lead a team of ML engineers, design end-to-end ML infrastructure, and drive data-driven evaluation while collaborating closely with Product and Engineering to achieve business goals.