Databases · head to head
FaunaDB vs Postgres
FaunaDB
Databases
Document-relational database whose hosted service closed in 2025 and whose core is now unmaintained Apache 2.0 code.
- From
- Free
- Rated
- -
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.; Postgres each major version is supported for only 5 years after its initial release, after which it is end-of-life
- They diverge on capability: FaunaDB covers Document-relational model, Postgres covers ACID compliance.
- Prices and features above were last checked on 30 August 2026.
Where they differ
Only the attributes on which FaunaDB and Postgres actually diverge.
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 FaunaDB
- Document-relational model
- FQL v10
- Distributed ACID transactions
- HTTPS access
- User-defined functions
- Attribute-based access control
- Document history
- Event streaming
Only in Postgres
- ACID compliance
- Complex queries
- Foreign keys
- Triggers
- Views
- Stored procedures
- JSON/JSONB support
- Full-text search
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 Postgres
- Extracting historical data from a Fauna dataset that can no longer be reached through the hosted APInot Postgres
- Studying a production implementation of deterministic distributed transactions, since the full server source is now readable under Apache 2.0not Postgres
- Forking the engine deliberately, where an organisation has JVM and distributed-systems staff and wants a document-relational store it fully controlsnot Postgres
Postgres
- Running a general purpose relational database for applicationsnot FaunaDB
- Self-hosting an open source SQL database with no licence feenot FaunaDB
- Workloads needing extensions, JSON and full text search in one enginenot 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.
Postgres
- Each major version is supported for only 5 years after its initial release, after which it is end-of-life
- Major version upgrades break on-disk compatibility and require a full dump and reload or the pg_upgrade tool
- New major versions ship about once a year, so staying supported means a disruptive upgrade cycle
- Minor releases contain only frequently-encountered bug fixes, low-risk fixes, security issues and data corruption fixes, so feature gaps are not addressed within a major version
- There is no vendor SLA; commercial support must be bought separately from third party professional services listed by the project
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
Postgres
Free- Community EditionFree
- Full database features
- No limitations
- 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.
Choose Postgres if
- You need acid compliance.
- You want to start without paying.
- You work on Linux, Windows, Macos, Docker.
- You also want complex queries.
Questions people ask
- Is FaunaDB or Postgres better?
- Neither clearly leads. FaunaDB starts at Free and Postgres at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
- Which is cheaper, FaunaDB or Postgres?
- FaunaDB starts at Free and Postgres at Free.
- Does FaunaDB or Postgres run on more platforms?
- FaunaDB runs on Web. Postgres runs on Linux, Windows, Macos, Docker.
- 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 Postgres is typically brought in for.
- What can FaunaDB do that Postgres cannot?
- FaunaDB covers Document-relational model, FQL v10, Distributed ACID transactions, HTTPS access. Postgres covers ACID compliance, Complex queries, Foreign keys, Triggers.
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.
Postgres: How much does PostgreSQL cost to use?
PostgreSQL is completely free to download, install, and use. No licensing fees, subscription costs, or per-seat charges apply. The database is open source under the PostgreSQL License. Source: https://www.postgresql.org
SourceFaunaDB: 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.
Postgres: Are there commercial PostgreSQL support options available?
Official PostgreSQL (the project) is free. Commercial PostgreSQL services such as hosting, professional support, training, and managed database services are offered by third-party vendors, not the PostgreSQL project itself. Source: https://www.postgresql.org
SourceFaunaDB: 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.
Postgres: Do I need a license to use PostgreSQL commercially?
No. PostgreSQL is open source under the PostgreSQL License, which permits free commercial use without royalties, licensing fees, or support obligations. Source: https://www.postgresql.org
SourceFaunaDB: 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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