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Databases · head to head

Estuary vs FaunaDB

Estuary logo

Estuary

Databases

Real-time data integration combining streaming, CDC, and batch

From
Free
Rated
-
Full reviewWebsite
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

The short version

  • Each has a real cost: Estuary per-GB pricing adds up quickly for high-volume scenarios; 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.
  • They diverge on capability: Estuary covers Real-time data delivery, FaunaDB covers Document-relational model.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Estuary and FaunaDB actually diverge.

Attributes where Estuary and FaunaDB differ
AttributeEstuaryFaunaDB
Pricing modelUsage-based per GB plus per-connector costfreemium
PlatformsCloud, Private Cloud, BYOCWeb
Founded20192012

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 Estuary

  • Real-time data delivery
  • Change data capture
  • Batch processing
  • Data transformation
  • Pre-built connectors
  • Multiple deployments
  • RBAC and monitoring

Only in FaunaDB

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

What people use each for

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

Estuary

  • Real-time data replication to data warehousesnot FaunaDB
  • Change data capture from operational databasesnot FaunaDB
  • Feeding analytics and BI systems with fresh datanot FaunaDB
  • Powering real-time AI and ML data pipelinesnot FaunaDB

FaunaDB

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

Where each one falls short

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

Estuary

  • Per-GB pricing adds up quickly for high-volume scenarios
  • No transparent per-connector volume discounts below 6 connectors
  • Limited to data movement; transformation capabilities are basic
  • BYOC and private deployment requires enterprise plan
  • Smaller ecosystem compared to established alternatives

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.

Pricing, plan by plan

Estuary

Free
  • DeveloperFree
    • 10 GB per month
    • 2 connector instances maximum
    • No credit card required
  • Cloud$0.5/GB
    • $0.50 per GB of data moved
    • $100 per connector monthly (6+ connectors $50 each)
    • 200+ connectors
  • Enterprise$null/custom
    • Volume-based discounts
    • SOC 2 and HIPAA compliance
    • SSO authentication

FaunaDB

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

Which should you pick?

Choose Estuary if

  • You need real-time data delivery.
  • You want to start without paying.
  • You work on Cloud, Private Cloud, BYOC.
  • You also want change data capture.
Estuary review

Choose FaunaDB if

  • You need document-relational model.
  • You want to start without paying.
  • You also want fql v10.
FaunaDB review

Questions people ask

Is Estuary or FaunaDB better?
Neither clearly leads. Estuary starts at Free and FaunaDB at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Estuary or FaunaDB?
Estuary starts at Free and FaunaDB at Free.
Does Estuary or FaunaDB run on more platforms?
Estuary runs on Cloud, Private Cloud, BYOC. FaunaDB runs on Web.
Can I use Estuary for free?
Both have a free tier, so you can try either at no cost before committing.
What is Estuary best used for?
Estuary is most often used for real-time data replication to data warehouses, change data capture from operational databases, feeding analytics and bi systems with fresh data, powering real-time ai and ml data pipelines. Of those, real-time data replication to data warehouses and change data capture from operational databases are not what FaunaDB is typically brought in for.
What can Estuary do that FaunaDB cannot?
Estuary covers Real-time data delivery, Change data capture, Batch processing, Data transformation. FaunaDB covers Document-relational model, FQL v10, Distributed ACID transactions, HTTPS access.

Answered from the vendors’ own pages

Estuary: What is included in the free Developer plan?

Developer plan ($0/month) includes 10 GB of data per month and up to 2 connector instances, no credit card required.

Source
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.

Estuary: How is data pricing calculated on Cloud plan?

Cloud plan charges $0.50 per GB of data moved plus $100/month per connector for the first 6 connectors, then $50/month for additional connectors.

Source
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.

Estuary: What discount is available when adding 6+ connectors?

When using 6 or more connectors, the per-connector cost drops to $50/month from $100/month, saving $50 per additional connector.

Source
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.

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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