Tech Leader - Recommendation Systems / Personalization

Cosmose, Inc.; Warszawa; On-site; PLN 350,000 - 520,000; Full time

Benefits offered by this job

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Job summary

Cosmose AI is seeking a Tech Leader to guide an established team building large-scale recommendation systems powering content discovery for millions of users. You will set the technical direction, drive ML-driven personalization, and collaborate with engineers, data scientists, and product teams to turn ideas into robust systems.

You will mentor engineers, help with hiring, and stay ahead of ML research to improve relevance, user experience, and scalability.

Qualifications

• Experience building high-scale distributed systems with ML components.
• Strong CS and applied math background including statistics and optimization.
• Bridge research ideas to production systems.
• Proficient in Python and ML libraries.
• Experience leading engineering and research teams.
• Thrives in fast-paced startup environments balancing speed and quality.
• Excellent Polish and English communication within a team.

Responsibilities

• Lead the recommendations team: define mission, roadmap, and day-to-day execution.
• Design, prototype, and deploy ML models for content personalization.
• Collaborate with product, engineering, and data teams on research directions.
• Translate research into production-ready, scalable solutions.
• Mentor engineers and grow the team; contribute to hiring.
• Stay updated on ML research and bring insights to systems and strategy.
• Balance innovation with performance, reliability, and scalability.

Skills

Distributed systems

Python

Leadership

Communication

ML libraries

Research-to-production

Tools

Python

Job description

About Cosmose AI

We make smartphones smarter. Cosmose is integrated by eight phone makers, capturing first-screen real estate and first-party data to drive over 2 billion daily user interactions in 60+ countries.

Why Join Cosmose AI?

• Global Scale: Build a product natively integrated across eight major OEMs with access to first party data from millions of phones in over 60 countries.
• Elite Talent Density: Work alongside IOI and ACM-ICPC champions.
• High Autonomy, Fast Velocity: Take complete ownership with rapid deployment cycles and a flat org chart.
• Real Ownership: Earn stock options that directly tie your upside to our global growth and success.

We’re looking for a Tech Leader to guide an established team focused on building and evolving large-scale recommendation systems that power content discovery for millions of users. In this role, you’ll drive the technical direction of our recommendations platform, leveraging machine learning where it adds the most impact while ensuring ideas translate into robust, production-ready systems. You’ll partner closely with engineers, data scientists, and product teams to continuously improve relevance, personalization, and user experience.

What You’ll Do

• Lead the recommendations team - define the mission, guide the roadmap, and support day-to-day execution.
• Work with the team to design, prototype, and deploy ML models that drive content personalization.
• Collaborate with product, engineering, and data teams to identify impactful research directions that solve real user problems.
• Turn research into production-ready solutions, balancing innovation with performance, reliability, and scalability.
• Mentor and grow engineers, fostering a learning culture within the team.
• Contribute to hiring and shaping the team, bringing in top talent, and helping them succeed.
• Stay up-to-date with the latest in ML research and tech, and bring those insights to our systems and strategies.

What You’ll Need

• Experience in building high-scale distributed systems with ML components (e.g., Search, Ranking, Personalization, or AdTech)
• Solid foundation in computer science and applied mathematics, including statistics, optimization, and algorithms.
• A track record of bridging research and production - from academic ideas to real-world systems.
• Proficiency in Python, and working knowledge of ML libraries
• Experience in leading engineering and research teams
• Experience in a fast-paced, startup environment, balancing speed, pragmatism, and quality
• Clear and effective communication within the team (Polish and English are required)

What You’ll Enjoy

Cosmose provides employees with a great platform to immerse and learn about the most exciting, innovative, and disruptive technologies in offline behavior solutions, unveiling untapped opportunities and profits in the industry. The company constantly innovates to invent and apply world-class technologies with a rockstar engineering team, including four world championship programming medalists. You’ll be working with a strong leadership team backed by experience from various key strategic areas and many other driven & intelligent people across the company. Cosmose is a place where great culture and goals unite departments and individuals to achieve big milestones together.

We’re building something big—and we’re just getting started.

Read More On

TechCrunch, Business Insider