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Databases · head to head

NATS vs Weaviate

NATS logo

NATS

Databases

High-performance messaging system for cloud-native applications

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: NATS core NATS has no persistence at all, so messages are lost if no subscriber is listening; Weaviate the free tier caps at 100,000 objects, 1 GB of memory and a single collection
  • They diverge on capability: NATS covers Very low latency, Weaviate covers Vector and keyword search.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which NATS and Weaviate actually diverge.

Attributes where NATS and Weaviate differ
AttributeNATSWeaviate
Pricing modelOpen source, no licence feefreemium
PlatformsLinux, macOS, Windows, Docker, KubernetesLinux, Mac, Windows, Web
CategoryDatabasesMachine Learning
FoundedUnknown2019

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 NATS

  • Very low latency
  • JetStream
  • Single binary
  • Request-reply

Only in Weaviate

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

What people use each for

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

NATS

  • Service-to-service messaging where latency is the binding constraintnot Weaviate
  • Edge and IoT messaging where a lightweight broker mattersnot Weaviate
  • Replacing a heavier broker when the workload does not need its guaranteesnot Weaviate

Weaviate

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

Where each one falls short

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

NATS

  • Core NATS has no persistence at all, so messages are lost if no subscriber is listening
  • JetStream adds the durability but also the operational complexity NATS is chosen to avoid
  • A much smaller ecosystem than Kafka or RabbitMQ, with fewer connectors and integrations
  • Fewer people know it, so hiring and existing organisational knowledge favour the alternatives

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

NATS

Free
  • NATSFree
    • Full functionality
    • No usage limits
    • Community support

Weaviate

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

Which should you pick?

Choose NATS if

  • You need very low latency.
  • You want to start without paying.
  • You work on Linux, macOS, Windows, Docker, Kubernetes.
  • You also want jetstream.
NATS 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 NATS or Weaviate better?
Neither clearly leads. NATS 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, NATS or Weaviate?
NATS starts at Free and Weaviate at Free.
Does NATS or Weaviate run on more platforms?
NATS runs on Linux, macOS, Windows, Docker, Kubernetes. Weaviate runs on Linux, Mac, Windows, Web.
Can I use NATS for free?
Both have a free tier, so you can try either at no cost before committing.
What is NATS best used for?
NATS is most often used for service-to-service messaging where latency is the binding constraint, edge and iot messaging where a lightweight broker matters, replacing a heavier broker when the workload does not need its guarantees. Of those, service-to-service messaging where latency is the binding constraint and edge and iot messaging where a lightweight broker matters are not what Weaviate is typically brought in for.
What can NATS do that Weaviate cannot?
NATS covers Very low latency, JetStream, Single binary, Request-reply. Weaviate covers Vector and keyword search, Built-in vectorizers, GraphQL API, Multi-tenancy.

Answered from the vendors’ own pages

NATS: Is NATS free?

Yes, open source and CNCF-graduated. Synadia sells a managed service.

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
NATS: Does NATS persist messages?

Core NATS does not — it is fire-and-forget. JetStream adds persistence, streaming and replay when you need them.

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
NATS: NATS or Kafka?

NATS is far lighter and lower latency, and much simpler to run. Kafka is the answer when you need a durable replayable log and a large connector ecosystem.

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
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
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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