Lead Data Scientist (Ranking)

WELCOME TO OLX

At OLX, we work together to build a more sustainable world through trade.

We make it safe, smart, and convenient to buy and sell cars, find housing, get jobs, buy and sell household goods, and more. Our colleagues around the world help to serve millions of people around the world every month, through its well-loved consumer brands including OLX, Otodom, Property24.

Join OLX and see how far you can go.

JOIN THE OLX RANKING DATA SCIENCE TEAM 

The Ranking Data Science team at OLX is responsible for building and scaling ranking algorithms across OLX Europe. Our main goal is to help our stakeholders increase efficiency and performance by delivering state-of-the-art LTR algorithms across our platform to serve our customers when looking for items in our vast catalog. In a nutshell, you will be exposed to projects such as:

- Multiobjective optimisation (e.g., optimize for more than one revenue stream)

- Personalisation (user personalisation)

- LTR Framework (ability to train models capable of optimizing specific targets based on varying contexts within OLX’s sectors like Motors and Real Estate)

- Semantic Search (Integration and optimisation of the end-to-end search flow)

- etc..

Our team collaborates with product and tech teams from OLX, as well as the Motors and Real Estate verticals like Otomoto and Otodom, across the entire EU region. This means that our solutions need to scale to millions of data points and need to be designed to be reused in markets with similar characteristics. We think of experimentation as a tool to learn what our users want. We always start simple and fail fast. This way, we can create solutions that can be adapted to every market.

What you will be doing:

• Work in multi-functional teams with people from different backgrounds to build our Ranking algorithms, developing further our LTR Framework

• Partner with our Platform teams to get support for innovation (you will be given the opportunity to think outside of the box! 10x and not “only” 10% incremental value!)

• Find opportunities where data science will make an impact 

• Help to translate business requirements into machine learning projects

• Measure the impact of your models on company goals

• Collaborate with internal and external stakeholders. You will find a group of friendly people who want to collaborate with you to improve our platform capabilities and the user experience, and ultimately have fun together!

• You will work in multi-functional teams, in a diverse, multinational environment, filled with people from Portugal, Spain, Germany, Bulgaria, Romania, Poland, Ukraine, Kazakhstan, and Uzbekistan.

• Most importantly, you will have fun working with us :)

Who we are looking for:

• You should be located in Portugal, Spain, Poland, or Germany 

• You should have proven experience in Ranking and LTR algorithms

• Proficient in English with excellent written and oral communication skills!

• Strong presentation skills

• Able to work in diverse, multi-functional teams with people from different backgrounds

• Solid background in statistics and modeling

• Good knowledge of Python, which means having experience with at least one of the following: Scikit-Learn, TensorFlow, PyTorch, Pandas

• At least 4 years of (hands-on) experience with Machine Learning (supervised, unsupervised, etc.) 

• Very good knowledge of NLP and Deep Learning (Embeddings, Language Models, Transformers, etc.)

• Good knowledge of Generative AI and Large Language Models (LLMs)

• Good understanding of engineering best practices, that is: testing, CI/CD, monitoring, alerting, containers

• Hands-on experience with SQL

• Experience with MLOps

Nice to have:

• Exposure to other programming languages such as Kotlin, Java, Scala, etc

• Experience bringing models into production and serving models at scale

• Experience using AWS for deploying machine learning solutions

• Experience with building data pipelines using tools like Spark and Airflow

• Understanding of A/B testing and experimentation

• Exposure to MLOps tools

What we offer:

• Permanent contract (we don't offer B2B!)

• Salary + annual bonus up to 20% of your annual gross salary + tax deductible costs up to 60%

• Work with and impact all OLX websites

• Train and conference budget and free access to Udemy courses

• MacBook Pro or Windows Dell along with necessary accessories to make your work comfortable

• 100% remote work (and the possibility to work from our office in Poznan or Warsaw)

Diversity, Equity and Inclusion at OLX

OLX values diversity and welcomes applicants of all races, ethnicities, disabilities, ages, genders, sexual orientations, religions, backgrounds, and experiences to apply. If this role excites you, we encourage you to apply, even if you don’t meet all the requirements - you may be just the right fit for this or other opportunities with us!

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