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Databases · head to head

PostgreSQL vs Weaviate

PostgreSQL logo

PostgreSQL

Databases

The world's most advanced open source relational database

From
Free
Rated
-
Full reviewWebsite
Weaviate logo

Weaviate

Machine Learning

Open-source vector database

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: PostgreSQL requires manual scaling across multiple machines for very large deployments; Weaviate the free tier caps at 100,000 objects, 1 GB of memory and a single collection
  • They diverge on capability: PostgreSQL covers ACID Compliance, Weaviate covers Vector and keyword search.

Where they differ

Only the attributes on which PostgreSQL and Weaviate actually diverge.

Attributes where PostgreSQL and Weaviate differ
AttributePostgreSQLWeaviate
Pricing modelUnknownfreemium
PlatformsLinux, Windows, macOS, BSD, UnixLinux, Mac, Windows, Web
CategoryDatabasesMachine Learning
Founded19962019

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in PostgreSQL

  • ACID Compliance
  • JSON/JSONB Support
  • Full-text Search
  • Extensibility
  • Advanced Indexing
  • Partitioning
  • Replication
  • pgAdmin

Only in Weaviate

  • Vector and keyword search
  • Built-in vectorizers
  • GraphQL API
  • Multi-tenancy
  • Hybrid search
  • OpenAI
  • Hugging Face
  • Cohere

Both cover

  • Linux support
  • Windows support
  • Mac support

What people use each for

The jobs each tool is most often brought in to do.

PostgreSQL

  • Transaction processingnot Weaviate
  • Data storagenot Weaviate
  • Application backendnot Weaviate
  • Reportingnot Weaviate
  • Data analyticsnot Weaviate

Weaviate

  • Running a vector database for semantic and hybrid searchnot PostgreSQL
  • Generating and storing embeddings alongside the objects they describenot PostgreSQL

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

PostgreSQL

  • Requires manual scaling across multiple machines for very large deployments
  • Performance tuning requires deep knowledge of database internals
  • No built-in graphical admin interface; command-line tools are primary method

Weaviate

  • The free tier caps at 100,000 objects, 1 GB of memory and a single collection
  • Billing is per million vector dimensions rather than per record, so wider embeddings cost proportionally more for the same object count
  • Premium is a prepaid contract starting at $400 a month rather than pay as you go
  • Storage rates do not fall consistently with tier, and Premium Dedicated is $0.1505 per GiB against $0.12 on the cheaper Flex plan
  • The Query Agent is metered separately, free to 1,000 requests a month and $30 a month plus overage beyond

Pricing, plan by plan

PostgreSQL

Free

No published plan breakdown. See the PostgreSQL review.

Weaviate

Free
  • Open SourceFree
    • Full features
    • Self-hosted
  • ServerlessFree
    • Managed service
    • Auto-scaling

Which should you pick?

Choose PostgreSQL if

  • You need acid compliance.
  • You want to start without paying.
  • You work on Linux, Windows, macOS, BSD, Unix.
  • You also want json/jsonb support.
PostgreSQL review

Choose Weaviate if

  • You need vector and keyword search.
  • You want to start without paying.
  • You work on Linux, Mac, Windows, Web.
  • You also want built-in vectorizers.
Weaviate review

Questions people ask

Is PostgreSQL or Weaviate better?
Neither clearly leads. PostgreSQL starts at Free and Weaviate at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, PostgreSQL or Weaviate?
PostgreSQL starts at Free and Weaviate at Free.
Does PostgreSQL or Weaviate run on more platforms?
PostgreSQL runs on Linux, Windows, macOS, BSD, Unix. Weaviate runs on Linux, Mac, Windows, Web.
Can I use PostgreSQL for free?
Both have a free tier, so you can try either at no cost before committing.
What is PostgreSQL best used for?
PostgreSQL is most often used for transaction processing, data storage, application backend, reporting. Of those, transaction processing and data storage are not what Weaviate is typically brought in for.
What can PostgreSQL do that Weaviate cannot?
PostgreSQL covers ACID Compliance, JSON/JSONB Support, Full-text Search, Extensibility. Weaviate covers Vector and keyword search, Built-in vectorizers, GraphQL API, Multi-tenancy. Both handle Linux support, Windows support, Mac support.

Answered from the vendors’ own pages

PostgreSQL: Is PostgreSQL completely free?

Yes. PostgreSQL is completely free and open source with no licensing fees or restrictions on use.

Source
Weaviate: What pricing options does Weaviate offer?

Weaviate provides a free tier with usage-based pricing, plus enterprise options. Visit the pricing page for detailed information on plans.

Source
PostgreSQL: What platforms does PostgreSQL run on?

PostgreSQL runs on all major operating systems including Linux, Windows, macOS, BSD, and commercial Unix variants, and has been proven highly scalable managing terabytes to petabytes of data.

Source
Weaviate: Does Weaviate offer customer support?

Yes, support is included with Weaviate's cloud offerings. Enterprise customers receive first-class support from their global team of experts.

Source
PostgreSQL: What procedural languages are supported?

PostgreSQL supports stored functions and procedures in multiple languages including PL/pgSQL, Perl, Python, Tcl, Java, JavaScript, R, and Rust.

Source
Weaviate: Can I deploy Weaviate on my own infrastructure?

Yes. Weaviate is open source and deployment-agnostic. You can run it in your own cloud environment or use their managed cloud service.

Source
PostgreSQL: What is ACID compliance in PostgreSQL?

PostgreSQL has been ACID-compliant since 2001, ensuring data integrity through atomicity, consistency, isolation, and durability guarantees for all transactions.

Source
Weaviate: What data security features does Weaviate provide?

Weaviate includes security & governance, RBAC, SOC 2 and HIPAA compliance, along with multi-tenancy and high availability for enterprise requirements.

Source
PostgreSQL: Does PostgreSQL support JSON data?

Yes. PostgreSQL supports JSON and JSONB data types for storing and querying JSON documents, along with XML and other document formats.

Source
Weaviate: How do I get started with Weaviate?

Sign up for their cloud tier, create your first dataset, connect an LLM, and build your AI app. Documentation and quickstart guides are available for Python, Go, TypeScript, and JavaScript.

Source
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