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Databases · head to head

FaunaDB vs NATS

FaunaDB logo

FaunaDB

Databases

Document-relational database whose hosted service closed in 2025 and whose core is now unmaintained Apache 2.0 code.

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: FaunaDB the hosted service was wound down in 2025, so there is no managed Fauna to buy; every remaining user either operates a JVM cluster themselves or migrates, and both are projects rather than tasks.; NATS core NATS has no persistence at all, so messages are lost if no subscriber is listening
  • They diverge on capability: FaunaDB covers Document-relational model, NATS covers Very low latency.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which FaunaDB and NATS actually diverge.

Attributes where FaunaDB and NATS differ
AttributeFaunaDBNATS
Pricing modelfreemiumOpen source, no licence fee
PlatformsWebLinux, macOS, Windows, Docker, Kubernetes
Founded2012Unknown

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 FaunaDB

  • Document-relational model
  • FQL v10
  • Distributed ACID transactions
  • HTTPS access
  • User-defined functions
  • Attribute-based access control
  • Document history
  • Event streaming

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.

FaunaDB

  • Keeping an existing Fauna-backed application alive on self-hosted infrastructure while a migration is planned and fundednot NATS
  • Extracting historical data from a Fauna dataset that can no longer be reached through the hosted APInot NATS
  • Studying a production implementation of deterministic distributed transactions, since the full server source is now readable under Apache 2.0not NATS
  • Forking the engine deliberately, where an organisation has JVM and distributed-systems staff and wants a document-relational store it fully controlsnot NATS

NATS

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

Where each one falls short

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

FaunaDB

  • The hosted service was wound down in 2025, so there is no managed Fauna to buy; every remaining user either operates a JVM cluster themselves or migrates, and both are projects rather than tasks.
  • The open-sourced repository has had no substantive activity since May 2025 and the drivers were frozen alongside it, so you inherit responsibility for security patches in a Scala distributed database that almost nobody else is running.
  • FQL has no wire or dialect compatibility with anything else, so migrating off is a rewrite of every query, index and access rule in the application rather than a data export.
  • No BI tool, ORM or CDC connector speaks FQL, so reporting and analytics always required exporting the data first, and that export tooling is now also unmaintained.
  • The community was small before the shutdown and has dispersed since, so operational answers, tuning advice and people who have run a Fauna cluster in anger are all scarce when something breaks.

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

FaunaDB

Free
  • FreeFree
    • 100K read ops
    • 50K write ops
    • 1GB storage
  • Pro$25/month
    • Pay per use
    • Priority support
    • Advanced features

NATS

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

Which should you pick?

Choose FaunaDB if

  • You need document-relational model.
  • You want to start without paying.
  • You also want fql v10.
FaunaDB 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 FaunaDB or NATS better?
Neither clearly leads. FaunaDB 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, FaunaDB or NATS?
FaunaDB starts at Free and NATS at Free.
Does FaunaDB or NATS run on more platforms?
FaunaDB runs on Web. NATS runs on Linux, macOS, Windows, Docker, Kubernetes.
Can I use FaunaDB for free?
Both have a free tier, so you can try either at no cost before committing.
What is FaunaDB best used for?
FaunaDB is most often used for keeping an existing fauna-backed application alive on self-hosted infrastructure while a migration is planned and funded, extracting historical data from a fauna dataset that can no longer be reached through the hosted api, studying a production implementation of deterministic distributed transactions, since the full server source is now readable under apache 2.0, forking the engine deliberately, where an organisation has jvm and distributed-systems staff and wants a document-relational store it fully controls. Of those, keeping an existing fauna-backed application alive on self-hosted infrastructure while a migration is planned and funded and extracting historical data from a fauna dataset that can no longer be reached through the hosted api are not what NATS is typically brought in for.
What can FaunaDB do that NATS cannot?
FaunaDB covers Document-relational model, FQL v10, Distributed ACID transactions, HTTPS access. NATS covers Very low latency, JetStream, Single binary, Request-reply.

Answered from the vendors’ own pages

FaunaDB: Can I still sign up for Fauna as a service?

No. Fauna Inc. wound down the hosted service in 2025 and the company website is no longer serving. The only way to run Fauna now is to build and operate the open-sourced server yourself.

NATS: Is NATS free?

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

FaunaDB: What licence is the open-sourced code under?

Apache 2.0, with the copyright held by a FaunaDB Foundation. That is a permissive OSI licence with no competing-use clause, so you may run it, modify it and even offer it as a service.

NATS: Does NATS persist messages?

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

FaunaDB: Is the open source version the same software that ran the cloud?

It is the core database engine. The control plane, billing, dashboard and multi-tenant operational tooling that made it a service are not part of the release, so you are running the engine, not the product.

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.

FaunaDB: What should I migrate to?

There is no drop-in target. Teams that valued the document model with relationships usually land on Postgres with JSONB, and teams that valued the serverless HTTP access pattern usually land on DynamoDB or a managed Postgres with an HTTP driver. Either way the query layer is rewritten.

FaunaDB: How hard is it to self-host?

It builds as a fat JAR and runs as a multi-node JVM cluster. There is an OPERATING.md, but no supported packaging, no operator, no upstream releases and no support contract, so budget for a distributed-systems engineer, not a container.

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