At myPOS, we’re all about helping businesses grow and get paid. We make payments simple, smart, and accessible for everyone, but we’re more than just payment solutions - myPOS is a partner in growth. From free multicurrency accounts to powerful e-commerce tools, we’re here to support business owners of all sizes and everyone out there who dreams of starting their own business.

As we are expanding our team, we’re looking for Senior Data Scientist to help us make a real difference in the Fintech industry. Ready to join us and shape the future of payments? Let’s make it happen!

About the role:

As a Senior Data Scientist at myPOS, you will be the technical cornerstone of a lean, high-calibre team. Reporting directly to the Head of Data Science, you will independently own and deliver the most complex modelling programmes - setting the technical standard and ensuring that model work reaches production and creates measurable commercial value.

This is a role for a data scientist who has outgrown purely executing on defined problems and is ready to shape how problems are framed, lead architectural decisions, and hold end-to-end accountability for outcomes - not just model performance.

What you’ll do:

• Own the full lifecycle of complex modelling programmes across Customer & Commercial Intelligence: CLTV, Churn Prediction, Propensity to Buy, and Next Most Likely Product (NMLP)

• Architect multi-horizon churn models and build the churn intervention scoring layer that prioritises at-risk merchants for Account Management teams

• Lead the NMLP engine — designing and productionizing a multi-output recommendation system that identifies the next product across myPOS's full catalogue

• Take technical ownership of core fraud model components: transaction-level classifiers, merchant behaviour anomaly detectors, and new-account fraud scorers optimised for high-throughput, low-latency inference

• Architect and own the Next Best Action (NBA) decisioning engine - a real-time system that selects the highest-expected-value action for each merchant at every interaction

• Design and build production-grade agentic AI systems that automate high-value analytical and operational workflows

• Define and execute experiment designs for online evaluation - A/B tests, uplift experiments, and bandits - and analyse results with statistical rigour

• Set and enforce technical standards across the team: code quality, reproducibility, evaluation rigour, model documentation, and MLOps practices

• Produce high-quality model documentation and present complex modelling work clearly to stakeholders across Sales, Marketing, Risk, Product, and Operations

This role is perfect for you if you have:

• MSc or PhD in Computer Science, Statistics, Applied Mathematics, Econometrics or a related quantitative field (or equivalent commercial experience)

• 7+ years of applied data science and ML experience in a commercial environment, with a strong portfolio of models in production that drove measurable business outcomes

• Expert Python for data science and ML engineering: pandas, scikit-learn, XGBoost / LightGBM, PyTorch or TensorFlow; clean, tested, modular code as a default

• Deep expertise across the ML methodological spectrum: survival analysis, time-series and sequence modelling, uplift and causal inference, anomaly detection, and recommendation systems

• Proven end-to-end ownership of at least three of: CLTV models, churn models, propensity models, fraud/risk models, recommendation or NBA systems - in a production commercial setting

• Strong MLOps capability: feature stores, model registries, model serving infrastructure, drift monitoring, and CI/CD for ML pipelines

• Deep SQL and data platform proficiency (GCP / BigQuery strongly preferred); experience with streaming architectures for real-time feature generation

• Hands-on expertise building LLM-powered applications: RAG pipelines, tool-use agents, multi-agent orchestration, and agent evaluation frameworks

• Strong experience with causal inference methods: uplift modelling, difference-in-differences, or instrumental variables

• Excellent communication: able to present complex technical work to senior business stakeholders and write high-quality model documentation

Nice to have:

• Experience in payments, fintech or financial services

• Experience with reinforcement learning or contextual bandits for ranking and decisioning

• Knowledge of graph neural networks for fraud or relationship modelling

• Familiarity with AI governance frameworks (EU AI Act, SR 11-7)

• Published research or open-source ML contributions

• Experience with real-time streaming inference (Flink, Spark Streaming)

Why you should join myPOS:

• Vibrant international team operating in hi-tech environment

• Annual salary reviews, promotions and performance bonuses

• myPOS Academy for upskilling and training

• Unlimited access to courses on LinkedIn Learning

• Annual individual training and development budget

• Refer a friend bonus as we know that working with friends is fun

• Teambuilding, social activities and networks on a multi-national level

What we offer:

• Excellent compensation package

• 25 days annual paid leave (+1 day per year up to 30)

• Full “Luxury” package health insurance including dental care and optical glasses

• Meal vouchers of 102.26 EUR per month

• Fully covered Multisport card

• Fully covered public transport pass for Sofia

• Free coffee, snacks and drinks at the office

Who we are:

Since 2014 we’ve been all about making payments easier and more accessible for businesses of all shapes and sizes. Whether you’re at the counter, selling online, or on the move, we’ve got businesses covered with smart, accessible and affordable solutions that keep things easy.

Our mission? It’s simple. Help businesses get paid by taking advantage of modern tech and innovative ideas, so payment challenges are a thing of the past.

Pro tip:

Take it easy about meeting every requirement - this job description is just that, a job description! Even if you don’t tick every box, we want you to apply anyway! This is your chance to grow, learn, and build your career with us. We value potential over perfection, and we are all about mutual growth!

Apply by filling in the form below and send your CV in English!

myPOS is committed to providing equal employment opportunities. All qualified candidates will be considered for employment without discrimination based on age, ancestry, color, marital status, national origin, physical or mental disability, medical condition, veteran status, race, religion, sex, sexual orientation, gender identity or expression, or any other characteristic protected by applicable laws, regulations, and ordinances.

Your application will be confidentially reviewed in line with the General Data Protection Regulation (GDPR). Personal information will be used solely for the job application and will be stored for a period needed by the application process. Only short-listed candidates will be contacted. Good luck!

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