Senior Software Engineer, Ontology & Reasoning Systems (819)

The role

You will design and build the ontology and reasoning layer that connects structured, semi-structured, and unstructured data into a model for deterministic machine reasoning. You will formalize complex domains into entities, relationships, constraints, and rules to derive explainable and traceable conclusions.

What you will do

• Own the ontology and rule layer that unifies enterprise data into a single reasoning model.
• Model entities, relationships, events, and constraints across heterogeneous sources.
• Develop rules that derive conclusions from combinations of facts.
• Use LLMs at the ingestion boundary for extraction, normalization, and categorization.
• Make system findings traceable by connecting conclusions to source facts and rules.
• Build retrieval capabilities including vector search, keyword search, and graph traversal.
• Improve quality through entity resolution, constraint modeling, and structured handling of sources.
• Ship production services and research prototypes.

Required qualifications

• 5+ years of experience building backend systems in a modern language such as Python, Go, Java, Scala, Rust, or similar, or equivalent practical experience.
• A strong formal and mathematical foundation, including discrete mathematics, logic, and graph theory.
• The ability to reason about soundness, completeness, and tractability, and to express complex domains as formal rules and constraints.
• Hands-on experience with declarative, logic-based, or rule-based reasoning systems such as Datalog, Answer Set Programming, constraint logic programming, Prolog, production rule engines, SMT solvers,
• Practical experience building LLM-powered systems, including structured extraction, RAG, or classification pipelines.
• Deep experience with knowledge graphs and graph data, including RDF, SPARQL, property graphs, or graph databases such as Neo4j.
• Experience designing systems whose outputs trace back to their inputs, including provenance, derivation chains, or evidence trails.
• Strong debugging, testing, and validation practices, with attention to correctness.

Nice to have

• Experience with constraint satisfaction or deductive reasoning, including CSP, unification, fixpoint or closure computation, or constraint propagation.
• Experience with formal ontology and semantics, including OWL, SHACL, description logics, or reasoners.
• Experience with LLM evaluation, entity resolution, citation validation, or hallucination reduction.
• Experience with symbolic computation, theorem proving, model checking, or formal verification.

Benefits

• Competitive salary
• Comprehensive benefits
• Generous vacation and holiday time off
• Access to ongoing learning & development

Before you apply

• You will be required to consent to and successfully complete a background investigation.
• Background investigation may include verification of extended education and additional criminal and civil checks.

About the company

Protegrity uses AI and quantum-resistant cryptography to transform data protection across cloud-native, hybrid, on-premises, and open source environments. The company is a global leader in data security.