Data Engineer, Ontologies & Knowledge Graphs (London)

Dex; Greater London; On-site; GBP 85,000 - 120,000; Full time

Job summary

Dex is seeking a specialist to design core semantic data foundations, turning messy APIs and data streams into unified knowledge graphs and queryable data products for autonomous AI agents. You will ensure data provenance, lineage, and secure classifications across multiple data stores while collaborating with domain experts in a fast-growing environment.

You will build and optimize pipelines and schemas, own migrations, and work across cloud and air-gapped environments to support secure,

Qualifications

• Strong experience building production-grade data pipelines and semantic data foundations.
• Expert in ontology development, identifiers, and versioning.
• Experience with secure data handling in regulated environments.

Responsibilities

• Design and evolve enterprise ontologies alongside domain experts, defining stable identifiers, relationship semantics, and schema versioning.
• Build ingestion and transformation pipelines that consolidate APIs, databases, unstructured files, and event streams into coherent graph, relational, and NoSQL data layers.
• Implement robust entity resolution, deduplication, and source reconciliation systems that keep data lineage and classification tags intact across every hop.
• Expose performant query interfaces and data retrieval services to downstream AI assistants and application services, enforcing automated semantic constraints.
• Own schema migrations, automated model validation, and deployment recovery strategies across cloud and air-gapped environments alongside DataOps.

Skills

Python

SQL

Graph databases

Cypher

RDF/SPARQL

Ontology design

Entity resolution

Data pipelines

Tools

Neo4j

RDF/SPARQL

Job description

Dex is seeking a specialist to design core semantic data foundations, turning messy APIs and data streams into unified knowledge graphs and queryable data products for autonomous AI agents. You will ensure data provenance, lineage, and secure classifications across multiple data stores while collaborating with domain experts in a fast-growing environment.

You will build and optimize pipelines and schemas, own migrations, and work across cloud and air-gapped environments to support secure,