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Databases · head to head

FaunaDB vs MotherDuck

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
MotherDuck logo

MotherDuck

Databases

Serverless analytics data warehouse built on DuckDB

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.; MotherDuck the free Lite plan caps compute at 10 hours per month, which limits it to light or hobbyist workloads.
  • They diverge on capability: FaunaDB covers Document-relational model, MotherDuck covers Serverless DuckDB instances.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which FaunaDB and MotherDuck actually diverge.

Attributes where FaunaDB and MotherDuck differ
AttributeFaunaDBMotherDuck
Pricing modelfreemiumusage-based
PlatformsWebweb, api
Founded20122022

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 MotherDuck

  • Serverless DuckDB instances
  • Cloud storage querying
  • MCP server
  • Dives
  • Flights
  • Read-scaling replicas

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

MotherDuck

  • Ad-hoc analytics on gigabyte-to-terabyte datasetsnot FaunaDB
  • Querying data lake files in S3/GCS/Azure without ingestionnot FaunaDB
  • AI agent data analysis via MCPnot FaunaDB
  • Scheduled data pipeline transformationsnot 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.

MotherDuck

  • The free Lite plan caps compute at 10 hours per month, which limits it to light or hobbyist workloads.
  • Business plan usage charges on top of the $250/month base can make costs less predictable than flat-rate competitors.
  • There are no academic or non-profit discounts, unlike some competing data platforms.
  • Annual billing requires going through a sales conversation rather than a self-serve toggle.

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

MotherDuck

Free
  • LiteFree
    • Up to 3 internal active users
    • 2 service accounts
    • 10GB free storage
  • Business$250/month
    • Up to 10 internal active users
    • Unlimited service accounts
    • 5 instance types with read-scaling replicas
  • Enterprise$undefined/month
    • Unlimited internal users and service accounts
    • Fixed-cost capacity pricing
    • AWS PrivateLink, IP allowlisting

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 MotherDuck if

  • You need serverless duckdb instances.
  • You want to start without paying.
  • You work on web, api.
  • You also want cloud storage querying.
MotherDuck review

Questions people ask

Is FaunaDB or MotherDuck better?
Neither clearly leads. FaunaDB starts at Free and MotherDuck at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, FaunaDB or MotherDuck?
FaunaDB starts at Free and MotherDuck at Free.
Does FaunaDB or MotherDuck run on more platforms?
FaunaDB runs on Web. MotherDuck runs on web, api.
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 MotherDuck is typically brought in for.
What can FaunaDB do that MotherDuck cannot?
FaunaDB covers Document-relational model, FQL v10, Distributed ACID transactions, HTTPS access. MotherDuck covers Serverless DuckDB instances, Cloud storage querying, MCP server, Dives.

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.

MotherDuck: What does MotherDuck cost?

The Lite plan is free (up to 3 users, 10GB storage, 10 hours of Pulse compute/month). Business is $250/organization/month plus usage, with Enterprise available at custom fixed-cost pricing.

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.

MotherDuck: Is there a free plan and what are its limits?

Yes, the Lite plan is free for up to 3 internal active users and 2 service accounts, with 10GB of storage and 10 hours of Pulse compute per month.

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.

MotherDuck: How is usage metered?

Compute instances (Pulse, Standard, Jumbo, Mega, Giga) are billed per second at hourly rates from $0.60 to $24.00/hour, storage is $0.04/GB-month, and AI Functions cost $1.00 per AI Unit.

Source
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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