---
title: 'Senior Software Engineer, Ontology & Reasoning Systems (819) at Protegrity'
canonical: 'https://feeny.ai/job/senior-software-engineer-ontology-reasoning-systems-819-protegrity-connecticut-da0cj1qez12s'
type: 'job'
last_seen: '2026-09-10'
---

# Senior Software Engineer, Ontology & Reasoning Systems (819) at Protegrity

- **Company:** Protegrity
- **Location:** Connecticut
- **Compensation:** $238k–$267k
- **Employment:** full-time
- **Work type:** hybrid
- **Posted:** 2026-06-25
- **Last confirmed live:** 2026-09-10
- **Apply:** https://jobs.ashbyhq.com/protegrity/facfdf47-481a-4d21-b6e3-14e32e963f0c/application

**Skills:** Python, Go, Java, Scala, Rust, Datalog, Answer Set Programming, Constraint logic programming, Prolog, Production rule engines, SMT solvers, LLM-powered systems, RAG, Knowledge graphs, RDF, SPARQL, Property graphs, Neo4j, Graph databases, Discrete mathematics

> Design and build the ontology and reasoning layer connecting structured and unstructured data into a deterministic machine reasoning model. Formalize complex domains into entities and rules, leveraging LLMs for ingestion and ensuring traceable, explainable conclusions.

## Job description

At Protegrity, we lead innovation by using AI and quantum-resistant cryptography to transform data protection across cloud-native, hybrid, on-premises, and open source environments. We leverage advanced cryptographic methods such as tokenization, format-preserving encryption, and quantum-resilient techniques to protect sensitive data. As a global leader in data security, our mission is to ensure that data isn’t just valuable but also usable, trusted, and safe.

Protegrity offers the opportunity to work at the intersection of innovation and collaboration, with the ability to make a meaningful impact on the industry while working alongside some of the brightest minds. Together, we are redefining how the world safeguards data, enabling organizations to thrive in a GenAI era where data is the ultimate currency. If you're ready to shape the future of data security, Protegrity is the place for you.

## Role Overview

Protegrity is seeking a Senior Software Engineer, Ontology & Reasoning Systems to design and build the ontology and reasoning layer that connects structured sources, semi-structured metadata, and unstructured documents into a model that supports deterministic machine reasoning.

In this role, you will formalize complex domains into entities, relationships, constraints, and rules that allow the system to derive conclusions from underlying facts. A key focus will be making those conclusions explainable and traceable, with clear derivation paths back to the source data and logic that produced them.

LLMs play an important role at the ingestion boundary, supporting extraction, normalization, and categorization of information from unstructured or ambiguous inputs. The reasoning layer itself must remain deterministic, auditable, and explainable, with appropriate checks on model-generated outputs before they are used as trusted facts.

You will work closely with product and research teams to define formal models, improve reasoning quality, and build systems that support accurate, reviewable outputs. This role is well suited for someone with a strong foundation in logic, graph-based systems, formal modeling, and production-grade software engineering.

## What You’ll Do

- Own the ontology and rule layer that unifies structured, semi-structured, and unstructured enterprise data into a single reasoning model.
- Model entities, relationships, events, and constraints across heterogeneous sources, and develop rules that derive conclusions from combinations of facts.
- Use LLMs at the ingestion boundary for extraction, normalization, and categorization, with appropriate validation of model-generated outputs.
- Make system findings traceable by connecting each conclusion to the source facts and rules that produced it.
- Build retrieval capabilities, including vector search, keyword search, and graph traversal, to support reasoning workflows.
- Improve quality through entity resolution, constraint modeling, and structured handling of conflicting or overlapping sources.
- Ship production services and research prototypes with a focus on correctness, reliability, and maintainability.

## What You’ll Need

- 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, or similar.
- Practical experience building LLM-powered systems, including structured extraction, RAG, or classification pipelines, with sound judgment about where model outputs require validation.
- 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.

Should you accept this position, you will be required to consent to and successfully complete a background investigation. This may include, subject to local laws, verification of extended education and additional criminal and civil checks.

We offer a competitive salary and comprehensive benefits with generous vacation and holiday time off. All employees are also provided access to ongoing learning & development.

Ensuring a diverse and inclusive workplace is our priority. We are committed to an environment of acceptance where you are free to bring your full self to work. All qualified applicants and current employees will not be discriminated against on the basis of race, color, religion, sex, sexual orientation, gender identity, age, national origin, disability or veteran status.

Please reference Section 12: Supplemental Notice for Job Applicants in our [Privacy Policy](https://www.protegrity.com/privacy-policy) to inform you of the categories of personal information that we collect from individuals who inquire about and/or apply to work for Protegrity USA, Inc., or its parent company, subsidiaries or affiliates, and the purposes for which we use such personal information.

## About Protegrity

## Company Overview
- **One-liner**: Protegrity provides a unified data-centric security platform that enables enterprises to protect sensitive data across clouds, analytics, and AI while staying compliant.
- **Entity Type**: Private (funding stage not publicly disclosed)
- **Headquarters**: Stamford, Connecticut, United States
- **Founded**: 1996
- **Founders**: Not publicly available

## Core Business
- **Primary industry**: Computer and Network Security / Data Protection
- **Target customers**: B2B – large enterprises across regulated industries (finance, healthcare, tech)
- **Mission or purpose statement**: "Protect the world’s most sensitive data wherever it resides" and "Activate Data. Secure Knowledge. Trust AI." (from protegrity.com)

## Products & Services
- **ProtegrityAI Enterprise Edition**: Centralized data protection for hybrid environments – includes discovery, governance, protection (tokenization, encryption, masking), privacy (anonymization, synthetic data), and semantic guardrails for AI. [protegrity.com/product]
- **ProtegrityAI Team Edition**: Deployed for departmental workloads with data-level protection and policy controls for faster, safer innovation. [protegrity.com/product]
- **ProtegrityAI Developer Edition**: Drop-in APIs for notebooks, CI/CD, and pipelines to protect real data during build/test with guardrails for prompts and outputs. [protegrity.com/product]
- **Additional offerings**: Secure Agents, Secure Inferencing, Compliance controls, Quantum-resilient data protection. [protegrity.com]

## Market Standing
- **Valuation / Market Cap**: Not disclosed
- **Key Metric**: Annual Revenue – USD 74.5M (LinkedIn estimate)
- **Notable Investors / Partners**: Not publicly available (parent company is Xcelera Inc. per LinkedIn)
- **Growth Signals**: 
  - Headcount: 263 employees (‑0.8% YoY) [LinkedIn]
  - Operates in 15 countries including India, UK, Portugal, Sweden, Singapore [LinkedIn]
  - Over 120 patents granted/pending, 20+ years in data security [protegrity.com/about-us/our-company]
  - LinkedIn followers: 28,513 (+6.4% yearly) [LinkedIn]

## Competitive Advantages
- **Data-centric protection** that works consistently across clouds, data platforms, models, and analytics – not tied to a single infrastructure.
- **Over 120 patents** and a two‑decade track record of innovation in data privacy/security.
- **Integrated AI security** – protects data at the layer before AI interacts with it (retrieval, reasoning, output), enabling safe use of enterprise knowledge.
- **Quantum resilience** – preparing for post‑quantum threats (mentioned in career page and CEO bio).

## Strategic Focus
- **Enabling secure AI adoption**: Protecting sensitive data used in AI agents, RAG workflows, training pipelines, and model inferencing.
- **Quantum‑safe security**: Building defenses that remain effective in a post‑quantum era.
- **Expanding platform capabilities**: Continuing to unify discovery, governance, protection, and privacy into a single control plane.

## Why Work Here
- **Culture**: "Bold thinking, technical excellence, and a drive to make a global impact" – collaboration, curiosity, continuous learning. [protegrity.com/about-us/careers]
- **Work environment**: Operates in 15 countries; remote/hybrid policy not explicitly stated but global presence suggests flexibility.
- **Benefits** (varies by region): Medical/dental/vision, 401K/pension, 15–25 days annual leave, paid parental leave, learning & development reimbursement, Employee Assistance Program, long‑term disability. [protegrity.com/about-us/careers]
- **Engineering focus**: Work on "cutting edge AI innovation with quantum safe technologies"; technical roles make up 37% of workforce. [LinkedIn]
- **Hiring process**: Human‑reviewed résumés, conversations with hiring manager and senior leadership, final interview with exec. [protegrity.com/about-us/careers]

## Sources
1. [Protegrity Homepage](https://www.protegrity.com/)
2. [Protegrity About Us](https://www.protegrity.com/about-us/our-company)
3. [Protegrity Careers](https://www.protegrity.com/about-us/careers)
4. [Protegrity LinkedIn](https://www.linkedin.com/company/protegrity)
5. [Protegrity Products](https://www.protegrity.com/product)

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