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Hybrid RAG + Knowledge Graph

3 search methods × RRF fusion — RAGAS faithfulness 0.91 on 200 questions over corporate documentation (3K+ pages)

At a glance
RAGAS faithfulness: 0.67 → 0.91 (on 200 control questions)

Architect & sole developer

2 мес · solo

  • Python
  • Qdrant
  • Neo4j
  • Sentence-Transformers
  • RAGAS
  • FastAPI
Knowledge OS — knowledge map (graph)

Knowledge OS — knowledge map (graph)

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Problem

What doesn't work

Vector search finds semantically similar documents but misses exact matches and entity relationships. Pure RAG over 3K+ page corporate documentation gives RAGAS faithfulness 0.67 — every third answer is incomplete or inaccurate.

Solution

Architectural approach

Three parallel search methods: Vector (Qdrant HNSW), BM25 (exact matches), Knowledge Graph (Neo4j, entity relationships). Results combined via Reciprocal Rank Fusion (RRF). Quality measured through RAGAS eval on 200 control questions.

My role & contribution

Architect & sole developer

Designed and built from scratch: Qdrant HNSW setup, Neo4j knowledge graph with entity resolution, BM25 index, RRF fusion with weight tuning. Ran RAGAS eval on 200 control questions. Deployed as internal tool for corporate documentation.

Ready to discuss?

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Serbia-based · CET/CEST timezone · EU-aligned working hours · International contracts experience