Guide
Best Vector Databases
Vector databases store embeddings and run fast similarity search — the retrieval layer behind RAG, semantic search, and recommendations in AI applications. The category includes purpose-built engines optimised for billion-scale nearest-neighbour search, managed serverless services, and lightweight libraries ideal for prototyping. The right choice depends on scale, whether you want managed or self-hosted, and how much filtering, hybrid search, and operational tooling you need. Consider index types, performance at your data size, and pricing that often scales by stored vectors or dimensions. Below are the most popular vector databases, compared on features, pricing, and the AI workloads they serve best.
5 tools reviewed
Why this matters
As AI apps rely on retrieval, the vector store becomes core infrastructure. The right one balances search quality, scale, and cost — and choosing between managed and self-hosted early avoids painful migrations later.
Featured tools
The open-source embedding database for AI apps.
Open-source vector database built for scalable similarity search.
The vector database for building knowledgeable AI.
High-performance vector database for the next generation of AI apps.
Open-source AI-native vector database.
Comparison table
| Tool | Free plan | Pricing model | Starting price | Best for |
|---|---|---|---|---|
| ✓ Yes | open source | Free plan | Startup, SMB | |
| ✓ Yes | open source | Free plan | Startup, SMB, Enterprise | |
| ✓ Yes | freemium | Free plan | Startup, SMB, Enterprise | |
| ✓ Yes | freemium | Free plan | Startup, SMB, Enterprise | |
| ✓ Yes | freemium | Free plan | Startup, SMB, Enterprise |
Popular comparisons
Frequently asked questions
What is a vector database used for?+
Storing embeddings and finding the most similar items quickly — powering retrieval-augmented generation (RAG), semantic search, and recommendations.
Do I need a dedicated vector database?+
Not always — some relational databases support vector search via extensions. Dedicated engines win at large scale, high query volume, or advanced filtering.
Managed or self-hosted?+
Managed services remove ops and offer free tiers to start; open-source engines can be self-hosted for control and cost savings at scale.
How is a vector database priced?+
Often by number of vectors, dimensions stored, or compute — with free tiers for small workloads and usage-based scaling beyond.