AI and Knowledge Graph Engineer

Location: Europe, Ukraine; remote

Company

hirify.global is building an AI-driven, end-to-end recruitment SaaS platform that automates the recruitment lifecycle, including candidate matching, communication, interviews, onboarding, and payroll processes.

What you will do

• Design, develop, and maintain production-ready Python services for information extraction, entity resolution, and semantic search.
• Build and evolve RDF-based knowledge graphs, including ontology design, semantic relationships, provenance, and temporal context.
• Develop SPARQL queries, graph ingestion pipelines, RDF validation, incremental updates, idempotent processing, and full rebuilds.
• Build NLP pipelines for documents, forms, messages, and transcripts, including entity matching, normalization, similarity scoring, and resolution.
• Improve lexical, vector, and hybrid search using embeddings, reranking, and graph queries; evaluate models with labeled datasets and precision/recall metrics.
• Ensure reliability through automated testing, monitoring, fault diagnosis, responsible AI practices, and collaboration on architecture and technical decisions.

Requirements

• 3+ years of experience in AI/ML engineering, Knowledge Graph Engineering, or Semantic Data Engineering.
• Hands-on experience developing and deploying production AI services and RDF-based knowledge graphs.
• Strong Python skills, including FastAPI, Pydantic, and SQL.
• Practical experience with RDF, SPARQL, ontology design, semantic data modeling, SHACL validation, taxonomies, and knowledge graph standards.
• Experience with RDF graph databases such as GraphDB, Stardog, Apache Jena, Amazon Neptune, or similar.
• Experience with NLP, information extraction, entity resolution, embeddings, semantic search, hybrid retrieval, and reranking.
• Experience building reliable data ingestion and transformation pipelines, with automated testing, data validation, production debugging, asynchronous processing, timeouts, retries, and error handling.
• Familiarity with model evaluation using precision, recall, and labeled datasets.
• Upper-Intermediate English level or higher.
• Strong analytical, problem-solving, and communication skills.

Nice to have

• Experience with Microsoft Foundry, Azure ML, MLflow, Azure AI Search, or OpenSearch.
• Experience with PyTorch, sentence-transformers, spaCy, or scikit-learn.
• Knowledge of SKOS, PROV-O, JSON-LD, and OWL reasoning.
• Experience with Parquet, Delta Lake, or learning-to-rank approaches.
• Understanding of event-driven architectures and distributed systems.

Culture & Benefits

• Remote work with a flexible working schedule.
• Up to 20 working days of vacation, 10 working days of sick leave, and up to 11 national holidays off.
• Medical reimbursement or insurance after 3 months.
• Online English courses and direct cooperation with the customer.
• Online and offline teambuildings and support for a volunteering culture.
• Full-time, long-term engagement.