Senior Data Scientist

👫 Who are we looking for? We’re looking for a business-oriented Senior Data Scientist who will help us shape and scale how ROI Hunter leverages product data to improve advertising profitability of our clients.
You will be the first dedicated data science hire at ROI Hunter, working closely with our Product, Engineering, and Design teams to automate product segmentation, uncover high-ROI opportunities, and build models that will make a tangible impact on customer performance.

🧰 Tools we use: SQL, BigQuery, DBT, Kotlin (with Spring Boot), Python, Google Cloud ecosystem (Cloud Run, Cloud Storage, PubSub, ...)

🌍 Where? Ideally Brno, South Moravia, or remote from Czechia

🗓️ When? We would ideally like to have a new colleague in Summer 2025

What we do

ROI Hunter powers high-performance e-commerce advertising on social media, trusted as an official Business Partner of Meta and Snapchat. Built specifically for retailers managing extensive product catalogs, our platform helps brands effortlessly create stunning, data-driven image and video ads for millions of products—in just a few clicks. With rich product-level insights, we empower retailers to optimize campaigns at scale and drive profitable growth.

About the role

We’re at a turning point: our current product segmentation relies heavily on expert-defined rules. We want to shift toward scalable, automated decision-making that maximizes ROAS (Return on Ad Spend) for our clients and you can be a part of it.

You won’t be handed perfect datasets or ready-made problems.
You'll be expected to challenge assumptions, shape the approach, and push through ambiguity to create something valuable.
Your work will directly influence how our clients spend millions in advertising!

What you’ll do:

• Take ownership of product scoring algorithms used for automated ad spend optimization.
• Work hands-on with large volumes of data (tens of millions of SKUs) to uncover patterns and drive measurable uplift in ROAS.
• Translate product performance data into business insights and smart segmentation.
• Build and test models that make complex decisions understandable and actionable.
• Collaborate directly with product managers, engineers, and designers to deliver measurable outcomes.

What makes this role special:

• First hire in data science—freedom to set best practices, tools, and impact roadmap.
• Direct access to decision-makers and short feedback loops.
• Visible outcomes: Your models will drive real budget allocation for major global retailers.
• Business-first mindset: We prioritize impact, not complexity. Your work must be understandable, measurable, and practical.

This is a greenfield role: you will set the foundations for data science at ROI Hunter.

Who you are:

• You bring 5+ years of hands-on experience in a data-driven role — ideally in e-commerce, retail, or performance marketing.
• You’re confident in SQL and Python, and you’ve applied statistical modeling and machine learning to solve real business problems.
• You have a strong grasp of experiment design and A/B testing, and you know how to interpret results in a commercial context.
• You’re driven by impact over complexity — you build models that are actionable, not just elegant.
• You thrive in autonomous environments — ambiguity excites you, and you don’t wait to be told what to do.
• You communicate clearly and can translate technical insights for product managers, designers, and other non-technical stakeholders.
• You ask the hard questions and speak up when something doesn’t add up — always with a constructive mindset.
• You enjoy working cross-functionally and believe that collaboration improves outcomes.
• You’ve seen projects through end-to-end — from problem framing to model deployment and iteration.
• You’re ready to be the first data scientist in the company — and feel confident owning your domain, even when you’re the most senior expert in the room.

Our Culture and Values

At ROI Hunter, we deeply value people and relationships, perhaps even mo