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Databases · head to head

CosmosDB vs NATS

CosmosDB logo

CosmosDB

Databases

Globally distributed, multi-model database service from Azure

From
Free
Rated
-
Full reviewWebsite
NATS logo

NATS

Databases

High-performance messaging system for cloud-native applications

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: CosmosDB autoscale provisioned throughput enforces a minimum of 1,000 RU/s, billed hourly whether or not the database is used; NATS core NATS has no persistence at all, so messages are lost if no subscriber is listening
  • They diverge on capability: CosmosDB covers Global Distribution, NATS covers Very low latency.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which CosmosDB and NATS actually diverge.

Attributes where CosmosDB and NATS differ
AttributeCosmosDBNATS
Pricing modelusage-basedOpen source, no licence fee
PlatformsWeb, AzureLinux, macOS, Windows, Docker, Kubernetes
Founded1975Unknown

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

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 CosmosDB

  • Global Distribution
  • Multi-model APIs
  • Elastic Scaling
  • Five Consistency Levels
  • SLA-backed Latency
  • Automatic Indexing
  • Serverless
  • Azure Functions

Only in NATS

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

What people use each for

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

CosmosDB

  • Running a globally distributed multi model database on Azurenot NATS
  • Serving low latency reads and writes from multiple Azure regionsnot NATS
  • Storing document, key value and graph data behind a managed servicenot NATS

NATS

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

Where each one falls short

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

CosmosDB

  • Autoscale provisioned throughput enforces a minimum of 1,000 RU/s, billed hourly whether or not the database is used
  • Provisioned throughput is charged in every region the account is replicated to, so multi region accounts multiply the RU bill
  • Storage charges cover data, indexes and backups in each replicated region
  • Egress out of Azure and between regions is charged, though ingress is free
  • The free allowance is one account per Azure subscription, limited to 1,000 RU/s and 25 GB
  • RU/s rates vary by region and are only shown through the pricing calculator rather than a flat published rate

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

Pricing, plan by plan

CosmosDB

Free
  • Free TierFree
    • 1000 RU/s
    • 25GB storage
    • First 12 months
  • ServerlessFree
    • Pay per request
    • Auto-scaling
    • Event-driven workloads

NATS

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

Which should you pick?

Choose CosmosDB if

  • You need global distribution.
  • You want to start without paying.
  • You work on Web, Azure.
  • You also want multi-model apis.
CosmosDB review

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

Questions people ask

Is CosmosDB or NATS better?
Neither clearly leads. CosmosDB starts at Free and NATS at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, CosmosDB or NATS?
CosmosDB starts at Free and NATS at Free.
Does CosmosDB or NATS run on more platforms?
CosmosDB runs on Web, Azure. NATS runs on Linux, macOS, Windows, Docker, Kubernetes.
Can I use CosmosDB for free?
Both have a free tier, so you can try either at no cost before committing.
What is CosmosDB best used for?
CosmosDB is most often used for running a globally distributed multi model database on azure, serving low latency reads and writes from multiple azure regions, storing document, key value and graph data behind a managed service. Of those, running a globally distributed multi model database on azure and serving low latency reads and writes from multiple azure regions are not what NATS is typically brought in for.
What can CosmosDB do that NATS cannot?
CosmosDB covers Global Distribution, Multi-model APIs, Elastic Scaling, Five Consistency Levels. NATS covers Very low latency, JetStream, Single binary, Request-reply.

Answered from the vendors’ own pages

CosmosDB: Is there a free tier for Azure Cosmos DB?

Yes, Cosmos DB offers a free tier with 1,000 RU/s of throughput and 25 GB of storage per month for the lifetime of the account, available to new accounts.

Source
NATS: Is NATS free?

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

CosmosDB: How is Cosmos DB priced after the free tier?

Cosmos DB uses three billing models: provisioned throughput billed per request unit per second, vCore pricing for certain APIs, or serverless consumption pricing where you pay only for requests processed. Reserved capacity offers 20% discount for one year or 30% for three years.

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.

CosmosDB: Can I change my pricing model after choosing one?

No. Once you select a compute pricing model and API, they cannot be changed. This choice is permanent for that database.

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.

CosmosDB: Is there a trial period for Cosmos DB beyond the free tier?

Azure offers a 30-day free trial account for all Azure services. Additionally, Azure AI customers may be eligible for a 90-day free Cosmos DB subscription through the Azure AI Advantage program.

Source
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