Junior Data Scientist

About the role

At Preply, we power people's progress by making learning transformative and accessible. As a Junior Data Scientist, you will own the design and implementation of ML solutions that directly enable a remarkable user experience within the Preply marketplace. You will contribute to the data pipelines that power our ranking and matching models, working alongside senior engineers to ensure data quality and reliability. You will build and improve offline evaluation tooling and experiment analysis to measure model performance and guide future iterations. This role requires curiosity and a growth mindset, allowing you to learn quickly from feedback and iterate on solutions. You will own well-scoped components of larger AI projects under close guidance from experienced ICs. Ultimately, your work will shape the lives of learners and tutors across 175 countries by supporting the intelligence layer of our marketplace.

Key facts

What you'll do

• Building ML solutions that enable a remarkable user experience in the Preply marketplace.
• Contributing to data pipelines that power the team's ranking and matching models, with support from senior engineers.
• Building and improving offline evaluation tooling and data quality checks.
• Analyzing experiment results to help the team understand model performance and guide future iterations.
• Owning well-scoped components of larger AI projects, with close guidance from senior teammates.
• Supporting the development and maintenance of feature engineering workflows that feed neural ranking models.
• Collaborating with data and product teams to translate business requirements into data-driven solutions.
• Implementing monitoring for data quality and model behavior to uphold marketplace integrity.
• Participating in full lifecycle model development, from prototyping to production deployment.
• Documenting methodologies and findings to ensure reproducibility and clear communication.
• Working within a modern AI-native marketplace that leverages deep learning and multimodal data.
• Contributing to Trust & Safety systems, including fraud prevention and abuse detection initiatives.
• Supporting large-scale experimentation infrastructure that drives data-informed decisions.
• Translating complex analytical results into actionable insights for non-technical stakeholders.
• Continuously refining solutions based on feedback and performance metrics to maximize learning impact.

Requirements

• Strong understanding of machine learning fundamentals.
• Hands-on machine learning experience through internships, research, personal projects, or industry work.
• Experience with Python, Pytorch and Github.
• Curiosity, a growth mindset, and the ability to learn quickly from feedback.
• Familiar with AI tools to improve productivity and learning.
• English proficiency at B2 level or above.
• Able to work in Ukraine or remotely from anywhere in Ukraine.
• Available to work full-time hours as required for the role.
• Comfortable operating in a fast-paced, dynamic, and human-led tech environment.
• Committed to upholding marketplace integrity and Trust & Safety principles.

Practical notes

• The role is open to candidates based in Ukraine.
• You can work from our Kyiv hub or remotely from anywhere in Ukraine.

Why you'll love it at Preply

• An open, collaborative, dynamic and diverse culture;
• A generous monthly allowance for lessons on http://preply.com, Learning & Development budget and time off for your self-development;
• A competitive financial package with equity, leave allowance and health insurance;
• Access to free mental health support platforms;
• The opportunity to shape the lives of learners and tutors through language learning and teaching in 175 countries (and counting!).

OUR PRINCIPLES

• Care to change the world
• We are passionate about our work and care deeply about its impact to be life changing.
• We do it for learners
• For both Preply and tutors, learners are why we do what we do. Every day we focus on empowering tutors to deliver an exceptional learning experience.
• Keep perfecting
• To create an outstanding customer experience, we focus on simplicity, smoothness, and enjoyment, continually perfecting it as every detail matters.
• Now is the time
• In a fast-paced world, it matters how quickly we act. Now is the time to make great things happen.
• Disciplined execution
• What makes us disciplined is the excellence in our execution. We set clear goals, focus on what matters, and utilize our resources efficiently.
• Dive deep
• We leverage business acumen and curiosity to investigate disparities between numbers and stories, unlocking meaningful insights to guide our decisions.
• Growth mindset
• We proactively seek growth opportunities and embrace challenges.