Senior Knowledge Graph Engineer

SNI is serving as a trusted IT Outsourcing partner in line with the needs of World's most prestigious firms and carried out successful projects worldwide.
For one of our European clients, we are currently looking for a Senior Knowledge Graph Engineer.
Details:
Start date: ASAP
Duration: 1 month with extension
Work model: Fully remote, with occasional (quarterly) team sessions in Czech Republic
Working Hours: US Overlap required (preferred 14:00 - 19:00 CET)
Responsibilities:
Design, develop, and maintain OWL/RDF ontologies, taxonomies, semantic constraints, and domain mappings.
Build ingestion, transformation, and enrichment pipelines to convert structured and unstructured data into RDF datasets.
Write, optimize, and maintain SPARQL queries for graph traversal, filtering, and data retrieval.
Programmatically process RDF graphs, ontologies, and triple stores using Apache Jena and Oxigraph.
Connect knowledge graphs with LLM workflows, RAG architectures, and AI agents to enable grounded, semantic retrieval.
Develop clean production code in Java or Python, build REST/Semantic APIs, write automated tests, and document ontologies and graph architectures.
Skills:
Advanced hands-on experience with RDF, OWL, SPARQL, and serializations (Turtle, JSON-LD, RDF/XML, N-Triples).
Deep proficiency with Apache Jena and RDF graph stores/triple stores such as Oxigraph.
Strong software engineering background in Java and/or Python.
Experience integrating Knowledge Graphs with modern GenAI architectures (GraphRAG, hybrid retrieval, vector search, LLM grounding).
Proven track record building automated RDF data transformation, entity resolution, and ingestion pipelines.
Professional English proficiency.
SNI sp. z o.o. will process personal data for the purpose of the recruitment process in accordance with Data Privacy Policy. The data may also be stored and processed for future recruitment purposes, in accordance with the given consent.

Work arrangement
Yes