Qdrant vs Neo4j Choosing the Right Vector Database for Your AI Apps

Qdrant and Neo4j are two vector databases that serve different primary needs. Qdrant is perfect for pure vector search scenarios with high performance requirements, while Neo4j shines when combining vector similarity with graph relationships. The choice between the two should depend on specific needs, considering factors such as existing infrastructure, team expertise, and the benefits of additional graph database features. Thorough benchmarking using an open-source tool like VectorDBBench can help make a decision based on actual performance results rather than marketing claims or hearsay. Both Qdrant and Neo4j use Hierarchical Navigable Small World (HNSW) algorithm for vector search, but each has its own implementation, with Qdrant having a custom HNSW for high-dimensional vector spaces and Neo4j supporting vectors up to 4096 dimensions with both cosine and Euclidean similarity functions. Qdrant is great at flexible data modeling, storing vectors alongside payload data, while maintaining consistency through ACID compliant transactions. Neo4j handles data through its graph architecture, with support for vector indexes on node and relationship properties. Performance optimization mechanisms include automatic sharding and replication, on-disk text and geo indexing, intelligent caching, scalar, product, and binary quantization to reduce memory usage without compromising search quality. Qdrant's query system is built for vector search operations, while Neo4j queries are centered around its graph database heritage, integrating well with vector similarity searches. Ultimately, the choice between Qdrant and Neo4j depends on the specific use case, requiring evaluation based on actual performance results rather than marketing claims or hearsay.