Senior Data Engineer (Ontology & Knowledge Graphs)

Location: London, United Kingdom; hybrid work with regular attendance at the London office.

Company

hirify.global is a dual-use technology company building secure AI infrastructure for government and regulated enterprise, including air-gapped, on-premises, and cloud-based systems.

What you will do

• Define and evolve ontologies for organisational entities, relationships, classifications, and business rules with product teams and domain experts.
• Build ingestion and transformation pipelines from APIs, databases, documents, files, and events into canonical data models.
• Implement entity resolution, deduplication, source reconciliation, provenance tracking, and handling of conflicting or uncertain information.
• Design and maintain graph models, relational schemas, and NoSQL structures according to query and consistency requirements.
• Develop efficient queries and traceable data interfaces for applications, retrieval services, and AI tools.
• Own automated testing, permissions and retention handling, model evolution, migrations, backfills, deployment, and recovery with DataOps.

Requirements

• Strong production Python engineering experience, including maintainable and tested ingestion and transformation pipelines.
• Strong SQL experience with relational modelling, transactions, indexing, migrations, and query optimisation.
• Practical NoSQL experience with document or key-value modelling, indexing, and consistency trade-offs.
• Production experience designing, populating, and querying graph databases or triple stores, such as Neo4j with Cypher or RDF stores with SPARQL.
• Practical ontology design experience covering entity definitions, stable identifiers, relationship semantics, controlled vocabularies, constraints, and versioning.
• Understanding of property graphs and RDF-based knowledge graphs, including when each approach is appropriate.
• Experience integrating heterogeneous sources, resolving entity identity, and maintaining provenance and lineage.
• Experience handling incremental updates, deletions, schema changes, and automated data validation.
• Ability to translate ambiguous domain requirements into documented models, useful queries, and reliable data interfaces.

Culture & Benefits

• Office-first hybrid model with regular collaboration in the London office.
• Inclusive, compassionate, and flexible culture focused on employee empowerment.
• Equity and competitive salary.
• Employer pension contributions and private health insurance.
• Gym membership, company retreats, and meetups supporting work-life balance.