Senior Ontology Engineer

PixelRain AI is a small, agile, and fast-moving artificial intelligence company developing an AI-powered product lifecycle knowledge platform for a U.S. Department of War (DoW) customer. The platform is designed to transform complex technical documentation and engineering data into an interconnected, searchable, and actionable knowledge ecosystem that supports maintenance planning, engineering analysis, and mission-critical decision-making.

At the core of the solution is a governed data ingestion pipeline that processes technical documents and structures their information into an enterprise ontology and knowledge graph. This foundation enables relationships between technical systems, components, maintenance requirements, and engineering knowledge to be established, maintained, and leveraged by generative AI applications. These applications help automate the drafting of maintenance-planning products and provide engineering teams with contextual, source-cited answers to complex technical questions, improving access to institutional knowledge and supporting more informed, traceable decisions.

As an Ontological Engineer, you will help shape the knowledge foundations behind enterprise AI systems. This role is well suited to someone who enjoys bringing clarity to complex domains and creating formal models that enable people, data, and systems to work from a shared understanding.

Salary: 175,000 - 232,800

Active US Security Clearance Required

What you'll do

• Design, build, and maintain the enterprise ontology (BFO/CCO-aligned) and controlled vocabularies, and map source-system data into them.
• Define domain concepts, entities, categories, attributes, and relationships in formal ontologies.
• Standardize vocabularies to establish shared business or scientific meaning across systems and departments.
• Build and manage the knowledge graph: RDF triple store (Apache Jena/Fuseki or similar), SHACL validation, SPARQL queries.
• Build the governed ingestion path so extracted content lands in the graph with provenance and confidence, and connect the graph to retrieval and GenAI applications.
• Carry normal full-stack development work alongside the ontology work — Python services, web UI, AWS.
• Work in a small Scrum team; demo working software every sprint.

Requirements

• Active Secret OR Top Secret Clearance Required

• 5+ years of hands-on semantic-technology work: OWL, RDF/Turtle, SHACL, and SPARQL.
• Experience building ontologies aligned to an upper ontology — BFO and CCO strongly preferred.
• Production experience with a triple store (Apache Jena/Fuseki, RDF4J, or similar).
• Solid general software engineering: Python, APIs, Git — able to handle full-stack tasks (web + AWS), not ontology-only.
• Working familiarity with LLMs and RAG — you’ve connected structured knowledge to generative applications.

Benefits

As part of the hiring process, we will ask you to complete an identity verification process to ensure authenticity and protect against identity fraud. You are expected to be on camera during virtual interviews. By proceeding, you authorize the collection, processing, and use of your data for identity verification and security purposes.