pgvector vs Weaviate

Detailed side-by-side comparison to help you choose the right tool

pgvector

🔴Developer

AI Memory

pgvector is an open-source PostgreSQL extension for storing embeddings and running vector similarity search with SQL. It is best for teams already using PostgreSQL that want semantic search, RAG retrieval, or AI memory without operating a separate vector database, while accepting PostgreSQL scaling and tuning tradeoffs.

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Starting Price

Free

Weaviate

🔴Developer

AI Database

Weaviate review of vector and hybrid search, managed and open-source deployment, current cloud pricing, advantages, tradeoffs, and practical RAG use cases.

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Starting Price

Free

Feature Comparison

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FeaturepgvectorWeaviate
CategoryAI MemoryAI Database
Pricing Plans1 listed plan3 listed plans
Starting PriceFreeFree
Key Features
  • • Vector storage in PostgreSQL tables.
  • • Multiple distance operators for similarity search.
  • • HNSW graph indexing.
  • • Workflow Runtime
  • • Tool and API Connectivity
  • • State and Context Handling

pgvector - Pros & Cons

Pros

  • ✓Keeps embeddings and relational data in PostgreSQL.
  • ✓Uses SQL-native queries and joins.
  • ✓Supports transactional workflows with PostgreSQL semantics.
  • ✓Avoids adding a separate vector service for moderate workloads.
  • ✓Open-source license reduces software licensing friction.
  • ✓Works with common PostgreSQL clients and application frameworks.
  • ✓Supports hybrid search patterns with SQL filtering and text search.
  • ✓Benefits from PostgreSQL backup, replication, and operations tooling.
  • ✓Supports HNSW and IVFFlat indexing options.
  • ✓Can simplify RAG application architecture when PostgreSQL is already used.

Cons

  • ✗Performance may lag specialized vector databases for very large or distributed workloads.
  • ✗Requires PostgreSQL extension support and database administration.
  • ✗Limited to PostgreSQL-compatible deployments.
  • ✗Heavy vector queries can affect transactional database performance.
  • ✗No native multi-node vector search layer in pgvector itself.
  • ✗Index maintenance can be expensive for frequent embedding updates.
  • ✗Large indexes can require substantial memory.
  • ✗Advanced vector search features may require additional tooling.
  • ✗No built-in GPU acceleration.

Weaviate - Pros & Cons

Pros

  • ✓Combines vector, keyword, and hybrid retrieval
  • ✓Offers managed and self-hosted deployment
  • ✓Free cloud tier supports prototyping
  • ✓Publishes baseline and metered prices

Cons

  • ✗Retrieval quality requires careful evaluation
  • ✗Cloud cost has several usage dimensions
  • ✗Self-hosting transfers operations to the team
  • ✗Authorization-safe RAG needs more than a database

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🔒 Security & Compliance Comparison

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Security FeaturepgvectorWeaviate
SOC2—✅ Yes
GDPR—✅ Yes
HIPAA——
SSO—🏢 Enterprise
Self-Hosted✅ Yes🔀 Hybrid
On-Prem✅ Yes✅ Yes
RBAC—✅ Yes
Audit Log——
Open Source✅ Yes✅ Yes
API Key Auth—✅ Yes
Encryption at Rest—✅ Yes
Encryption in Transit—✅ Yes
Data Residency—US, EU
Data RetentionControlled by the PostgreSQL deployment and application policies.configurable
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