Senior Data Engineer - Ontology & Knowledge Graphs

You will design and build the data foundations that allow ACRA applications and Valarie to understand organisational information. Your work will turn heterogeneous sources into coherent entities, relationships and queryable data products across graph, relational and NoSQL databases.

Work with product teams and domain experts to define and evolve ontologies covering organisational entities, relationships, classifications and business rules.

Build ingestion and transformation pipelines from APIs, databases, documents, files and events into canonical data models.

Implement entity resolution, deduplication and source reconciliation, retaining provenance and handling conflicting or uncertain information.

Design and maintain graph models, relational schemas and NoSQL structures, choosing representations according to query and consistency requirements.

Develop efficient queries and data interfaces for applications, retrieval services and AI tools, with traceable results.

Implement automated tests for transformation correctness, semantic constraints, relationship integrity and source-to-target reconciliation.

Preserve source permissions, classification and retention requirements through derived datasets and graph relationships.

Own model evolution and migration logic, partnering with DataOps on deployment, backfills and recovery.

Strong production Python engineering and experience building maintainable, tested ingestion and transformation pipelines.

Strong SQL, including relational modelling, transactions, indexing, migrations and query optimisation.

Practical NoSQL experience, including document or key-value modelling, indexing and consistency trade-offs.

Production experience designing, populating and querying a graph database or triple store—for example, Neo4j with Cypher, or an RDF store with SPARQL.

Practical ontology design experience: clear 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.

Valarian Technologies Limited is an equal opportunity employer and welcomes applications from invdividuals regardless of race, colour, religion, sex, sexual orientation, gender, identity or expression, national origin, age, disability, genetic information, marital status, veteran, amnesty, or any other legally protected characteristic. We are committed to ensuring a fair and inclusive recruitment process and providing employment opportunities to all applicants. Decision recruitment, hiring, and employment are based solely on qualifications, skills, and experience relevant to the job requirements. We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analysing resumes, or assessing responses and identifying potential inconsistencies or verification signals in application materials based on available information. These tools assist our recruitment team but do not replace human judgement. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.