Data Scientist
Madfish
Data Science
Ukraine
Posted on Nov 28, 2025
We are looking for a Mid-to-Senior Data Scientist who can deliver end-to-end solutions, communicate both technical and business aspects to clients, and take ownership of production outcomes — helping Dastellar fulfill its mission to build custom AI/ML/Data Science solutions for businesses.
General Requirements
- Experience: 5+ years in ML/Data Science.
- LLMs / GenAI: hands-on experience deploying and fine-tuning LLMs (e.g., GPT/LLaMA/Hugging Face), building RAG/embedding pipelines and using LangChain or equivalents.
- Classical ML: proven work with sklearn, XGBoost/LightGBM, time-series methods (ARIMA/Prophet/ETS or deep models), recommendation systems.
- Python: daily use of Python 3.8+, solid Pandas/NumPy; experience with PyTorch or TensorFlow in at least one production project.
- Production: experience deploying models (Docker, CI/CD), setting up monitoring; basic cloud skills (AWS/GCP/Azure) preferred.
- Communication: experience presenting technical topics to clients and translating technical risks into business impact.
- Autonomy: history of leading end-to-end tasks without continuous supervision; ready to provide examples of decisions owned.
- Language: English — B2+.
Would be a plus
- Experience with vector DBs (FAISS, Qdrant, Pinecone).
- MLOps basics: experiment tracking (MLflow, W&B), CI/CD pipelines, automation tools.
- Big Data experience (Spark) and advanced SQL optimization.
- Deep domain knowledge in energy or retail.
Your main responsibilities are
- Design and deliver custom ML/GenAI solutions (POC to production).
- Build models: LLMs (fine-tuning, prompt engineering), embeddings, RAG; classic ML (classification, regression, time-series, clustering, recommender systems).
- Build ETL/ELT pipelines, feature engineering, data cleaning and validation.
- Design solution architecture and select the stack (deployment infra, vector DBs, orchestration).
- Deploy models and integrate with infra (Docker, CI/CD, optionally Kubernetes or serverless).
- Set up model and system monitoring (model metrics, data drift, alerts).
- Prepare technical documentation, proposals and client presentations.
- Conduct research and technical experiments; document R&D results.
- Perform code reviews, write tests and ensure code/model quality.
Soft Skills
- Responsibility: Met deadlines, maintained post-release SLAs and can provide project timelines with milestone outcomes as evidence.
- Proactivity: Proposed and implemented multiple processes or architecture improvements with measurable impact (reduced time-to-delivery or error rate), documented with a short case note describing outcome.
- Autonomy: Delivered milestones on multi-month projects with only weekly or biweekly syncs (no day-to-day supervision); able to produce independent milestone plans and status reports.
- Ownership: Owned multiple production ML services end-to-end - architecture, deployment, monitoring and incident resolution. Can present a 1-page case study showing decisions and results.
- Problem solving: Translated ambiguous business goals into a 2–4 sprint MVP roadmap with prioritized tasks, acceptance criteria and success metrics; provide an example roadmap or case.
- Critical thinking: Identified data/assumption biases or failure modes and proposed validation/mitigation tests.
What we offer
- Flexible part-time / contract work (compatible with other projects).
- Real client cases in energy and e-commerce.
- Fast decision-making and low bureaucracy.
- Opportunity to influence architecture and stack choices.
- Remote collaboration and flexible schedule.
- Paid R&D participation (by agreement).