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Cognee Architecture

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Why multiple stores

No single database can handle all aspects of memory. Cognee combines three complementary storage systems. Each one plays a different role, and together they make your data both searchable and connected.
  • Relational store — Tracks your documents, their chunks, and provenance (i.e. where each piece of data came from and how it’s linked to the source).
  • Vector store — Holds embeddings for semantic similarity (i.e. numerical representations that let Cognee find conceptually related text, even if the wording is different).
  • Graph store — Captures entities and relationships in a knowledge graph (i.e. nodes and edges that let Cognee understand structure and navigate connections between concepts).
Cognee ships with lightweight defaults that run locally, and you can swap in production-ready backends when needed (see Setup).

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What is stored where

Roughly speaking:
  • The relational store handles document-level metadata and provenance.
  • The vector store contains semantic fingerprints of chunks and DataPoints.
  • The graph store captures higher-level structure in the form of entities and relationships.
There is some overlap: for efficiency, parts of the same information may be indexed in more than one store.

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How they are used

The stores play different roles depending on the phase:
  • The relational store matters most during cognification, keeping track of documents, chunks, and where each piece of information comes from.
  • The vector and graph stores come into play during search and retrieval:
    • Semantic searches (vector): find conceptually related passages based on embeddings
    • Structural searches (graph): explore entities and relationships using Cypher directly
    • Hybrid searches (vector + graph): combine both perspectives to surface results that are contextually rich and structurally precise.

Main Operations

See how Add, Cognify, and Search use the storage systems

Building Blocks

Learn about DataPoints, Tasks, and Pipelines that feed into storage

Search

Explore different query types and modes that leverage the architecture