# Knowledge Graph

Extract entities, build knowledge graphs, and query relationships from your content.

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## Core Concepts

* [Observable/Observation Model](https://docs.graphlit.dev/api-guides/use-cases/knowledge-graph/observable-observation-model-explained) - **Start here** - Entity architecture
* [Entity Types Comprehensive](https://docs.graphlit.dev/api-guides/use-cases/knowledge-graph/observable-entity-types-comprehensive) - All 20+ types (12 medical included)
* [Confidence and Occurrences](https://docs.graphlit.dev/api-guides/use-cases/knowledge-graph/observable-confidence-and-occurrences) - Timestamps, pages, bounding boxes
* [Workflow Extraction Explained](https://docs.graphlit.dev/api-guides/use-cases/knowledge-graph/workflow-extraction-how-it-works) - How LLMs extract entities
* [Configure Entity Extraction](https://docs.graphlit.dev/api-guides/use-cases/knowledge-graph/workflow-configure-entity-extraction) - Workflow setup

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## End-to-End Examples

Build complete knowledge graphs from various sources:

* [From PDF Documents](https://docs.graphlit.dev/api-guides/use-cases/knowledge-graph/knowledge-graph-from-pdf-documents) - Most popular - Complete pipeline
* [From Emails](https://docs.graphlit.dev/api-guides/use-cases/knowledge-graph/knowledge-graph-from-emails) - Gmail/Outlook → contact networks
* [From Slack Messages](https://docs.graphlit.dev/api-guides/use-cases/knowledge-graph/knowledge-graph-from-slack-messages) - Team collaboration graphs
* [From GitHub Repositories](https://docs.graphlit.dev/api-guides/use-cases/knowledge-graph/knowledge-graph-from-github) - Contributors, repos, dependencies
* [From Meeting Recordings](https://docs.graphlit.dev/api-guides/use-cases/knowledge-graph/knowledge-graph-from-meetings) - Audio → transcript → entities
* [From Medical Content](https://docs.graphlit.dev/api-guides/use-cases/knowledge-graph/knowledge-graph-medical-content) - Clinical entity extraction (12 types)

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## Graph Queries

* [Relationship Queries](https://docs.graphlit.dev/api-guides/use-cases/knowledge-graph/observable-relationship-queries) - Person → Organization patterns
* [Advanced Graph Patterns](https://docs.graphlit.dev/api-guides/use-cases/knowledge-graph/observable-query-graph-patterns) - Subgraphs, centrality, paths
* [Entity Deduplication](https://docs.graphlit.dev/api-guides/use-cases/knowledge-graph/observable-entity-deduplication) - How Graphlit handles duplicates
* [Knowledge Graph Enrichment](https://docs.graphlit.dev/api-guides/use-cases/knowledge-graph/knowledge-graph-enrichment) - External data augmentation

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## Content + KG Integration

* [Filter Content by Entities](https://docs.graphlit.dev/api-guides/use-cases/knowledge-graph/content-filter-by-entities) - Find all content mentioning entity
* [Entity Co-Occurrence](https://docs.graphlit.dev/api-guides/use-cases/knowledge-graph/content-entity-co-occurrence) - Network analysis
* [KG-Guided Search](https://docs.graphlit.dev/api-guides/use-cases/knowledge-graph/knowledge-graph-guided-search) - Entity expansion
* [Entity Timeline](https://docs.graphlit.dev/api-guides/use-cases/knowledge-graph/observable-content-timeline) - First/last mentions
* [Export with Entities](https://docs.graphlit.dev/api-guides/use-cases/knowledge-graph/content-export-with-entities) - JSON/CSV export

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## Related Tutorials

* [Knowledge Graph Quickstart](https://docs.graphlit.dev/tutorials/knowledge-graph) - 20-minute complete tutorial

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