Senior Knowledge Graph Ontologist & Identity Architect

Sambatv; Warszawa; On-site; PLN 240,000 - 360,000; Full time

Job summary

Samba TV is seeking a Senior Ontologist to own design, development, and governance of its knowledge graph ontologies. You will write SPARQL, build pipelines, and ensure semantic models scale across data sources.

You will collaborate with data engineering and science peers, apply ML/AI where helpful, and mentor junior engineers in semantic modeling and graph best practices. This role reports to the Data Science Manager, Knowledge Graph & Identity.

Qualifications

• 5–8 years of hands‑on experience in ontology engineering, semantic data modeling, or knowledge graph development - with a demonstrable track record of production ontologies at scale
• Deep expertise in W3C semantic web standards: RDF, RDFS, OWL, SPARQL 1.1, and SHACL - with hands‑on experience building and validating graph schemas in a production triplestore (Amazon Neptune, Stardog, GraphDB, Jena, or equivalent)
• Strong Python - production‑quality, well‑tested code; comfortable building data pipelines and graph processing workflows
• First‑principles understanding of description logics, ontology design patterns, and the practical trade‑offs between OWL expressivity and triplestore scalability
• Hands‑on experience with entity resolution, record linkage, or deduplication at scale - mapping messy, multi‑source real‑world data to clean ontological representations
• Bachelor's degree required in Computer Science, Information Science, Computational Linguistics, Mathematics, or a related field; Master's or PhD strongly preferred
• Strong communicator - able to defend ontological modeling decisions in design reviews and explain trade‑offs to non‑specialist stakeholders

Responsibilities

• Own the end‑to‑end design, development, and versioning of Samba TV's core ontologies in RDF/RDFS/OWL - defining entity classes, properties, hierarchies, and constraints
• Author and maintain SHACL shapes for post‑load graph validation, consistency checking, and data quality enforcement
• Define and document derived‑attribute schemas - genre affinity, brand affinity, topic affinity, lifecycle signals, and viewing summaries
• Establish ontology design standards, change management processes, and versioning practices; evaluate alignment with W3C standards and relevant industry schemas
• Lead ontology design reviews with product, data engineering, and data science stakeholders - articulating trade‑offs between expressivity, scalability, and query performance clearly
• Define the aggregation and scoring logic that transforms raw TV viewership and web activity events into durable affinities, summaries, and inferred signals
• Co‑own derivation pipeline design with data engineering - specifying transformation logic, intermediate schemas, and validation checkpoints for Databricks/Spark pipelines
• Reason carefully about what belongs in the graph vs. what should remain virtualized in the data lake - balancing query performance against storage and refresh cost
• Build and maintain production‑quality knowledge graph pipelines in Python and SPARQL - well‑tested, documented, and scalable

Skills

Ontology engineering

Semantic data modeling

Knowledge graph development

Python programming

Entity resolution

Education

Bachelor's degree in Computer Science or related field

Master's or PhD preferred

Tools

Amazon Neptune

Stardog

GraphDB

Jena

PySpark

Databricks

Job description

Samba TV is seeking a Senior Ontologist to own design, development, and governance of its knowledge graph ontologies. You will write SPARQL, build pipelines, and ensure semantic models scale across data sources.

You will collaborate with data engineering and science peers, apply ML/AI where helpful, and mentor junior engineers in semantic modeling and graph best practices. This role reports to the Data Science Manager, Knowledge Graph & Identity.