Neo4j — The Leading Native Graph Database

What Neo4j Does

• Property graph — nodes, relationships, both with properties
• Cypher — SQL-like declarative query language (now ISO GQL standard)
• Index-free adjacency — constant-time traversal regardless of graph size
• ACID transactions — full consistency guarantees
• Clustering — Enterprise causal clustering for HA
• Graph algorithms — via Graph Data Science (GDS) library
• Vector search — Neo4j 5.11+ built-in vector indexes for RAG
• GraphQL — Neo4j GraphQL library to generate API

Architecture

Native graph storage: nodes and relationships are first-class records on disk with direct pointers (index-free adjacency). Query engine compiles Cypher to an execution plan that walks the graph. Bolt binary protocol for driver communication.

Self-Hosting

# docker-compose.yml
version: "3"
services:
  neo4j:
    image: neo4j:5-community
    ports: ["7474:7474", "7687:7687"]
    volumes:
      - neo4j-data:/data
      - neo4j-logs:/logs
    environment:
      NEO4J_AUTH: neo4j/tokrepo12345
      NEO4J_server_memory_heap_max__size: 2G
      NEO4J_PLUGINS: "[\"apoc\", \"graph-data-science\"]"
volumes:
  neo4j-data:
  neo4j-logs:

Key Features

• Native property graph storage
• Cypher query language
• ACID transactions
• Graph Data Science library (65+ algorithms)
• Vector indexes for AI/RAG
• Neo4j Browser UI
• Bolt binary protocol
• APOC stored procedures library
• Causal clustering (Enterprise)
• Fabric for multi-database queries

Comparison

FAQ

Q: When to choose a graph database? A: Social networks, recommendation systems, fraud detection, knowledge graphs, dependency analysis, identity auth chains — any query where relationships are central.

Q: Cypher vs Gremlin? A: Cypher is declarative (SQL-like); Gremlin is imperative (like a program). Cypher is more readable and has become the ISO GQL standard; Gremlin is more general (any TinkerPop graph).

Q: Vector search? A: Neo4j 5.11+ supports native vector indexes, enabling GraphRAG by combining vectors with graph structure — graph nodes can carry embeddings.

Sources

• Docs: https://neo4j.com/docs
• GitHub: https://github.com/neo4j/neo4j
• License: GPLv3 Community / commercial Enterprise