FerretDB
maintenanceby FerretDB Inc. · since 2022
Apache-licensed MongoDB-protocol proxy that stores data in PostgreSQL with the DocumentDB extension.
maintenance. No release since v2.7.0 (Nov 2025), commits stalled in early 2026 and ferretdb.com lapsed, after MongoDB's 2025 patent suit. Consider DocumentDB (Linux Foundation) instead.
Overview
FerretDB is a stateless Go proxy that accepts MongoDB wire-protocol traffic and translates it to PostgreSQL. Since 2.0 (early 2025) it requires the DocumentDB extension as its storage engine, which gave a big jump in compatibility and speed. It was the first serious attempt at a truly open-source MongoDB alternative, and the company launched FerretDB Cloud in 2025. Since then, momentum has collapsed. The last release is v2.7.0 (November 2025), the official website lapsed in 2026, and the project was hit by a patent suit from MongoDB. Treat it as a stalled project and look at DocumentDB directly for new work.
Strengths & trade-offs
Strengths
- +Apache 2.0 licensed and runs on infrastructure teams already operate (PostgreSQL)
- +Works with standard MongoDB drivers and mongosh
- +Stateless proxy design is easy to deploy alongside Postgres
Trade-offs
- −Development has effectively stopped since late 2025
- −No oplog, so change streams and replica-set-dependent tooling don't work
- −Multi-document transactions are not supported
- −Adds a translation hop on top of DocumentDB, which can now speak the protocol itself
Great for
- +Existing deployments already running FerretDB 2.x
- +Small apps such as LibreChat needing a MongoDB-compatible store on Postgres
Think twice for
- −New projects (choose DocumentDB or MongoDB)
- −Workloads needing change streams or transactions
Capabilities
Native or official first-party support · 6 of 25 tracked
Scale & consistency
- Comfortable data size
- Medium · ≤ 10 TB
- Horizontal scaling
- None
- Multi-region
- No
- Transactions
- Limited ACID
- Consistency
- Strong
- Schema
- Schemaless
- Architecture
- Client server, Primary replica
- Query languages
- MongoDB Query API (MQL), Aggregation pipeline
Bounded by the single PostgreSQL primary behind it; the proxy itself is stateless.
Deployment
Ecosystem
Alternatives to FerretDB
MIT-licensed, MongoDB-compatible document engine built as PostgreSQL extensions, run by the Linux Foundation.
ferretdb vs documentdb-postgres →The default document database: flexible BSON documents, rich queries and built-in sharding.
ferretdb vs mongodb →Drop-in MongoDB Community build with enterprise features like encryption, LDAP and hot backup.
ferretdb vs percona-server-mongodb →Microsoft's managed MongoDB-compatible service, built on the open-source DocumentDB engine.
ferretdb vs azure-documentdb →The extensible, standards-first open-source relational database.
ferretdb vs postgresql →CNCF-graduated sharding and clustering layer that makes a fleet of MySQL servers look like one database.
ferretdb vs vitess →FerretDB FAQ
What is FerretDB?
FerretDB is a document database by FerretDB Inc., first released in 2022. FerretDB is a stateless Go proxy that accepts MongoDB wire-protocol traffic and translates it to PostgreSQL. Since 2.0 (early 2025) it requires the DocumentDB extension as its storage engine, which gave a big jump in compatibility and speed. It was the first serious attempt at a truly open-source MongoDB alternative, and the company launched FerretDB Cloud in 2025. Since then, momentum has collapsed. The last release is v2.7.0 (November 2025), the official website lapsed in 2026, and the project was hit by a patent suit from MongoDB. Treat it as a stalled project and look at DocumentDB directly for new work.
Is FerretDB open source?
Yes. FerretDB is open source. License: Apache License 2.0.
Does FerretDB support ACID transactions?
Partly. FerretDB offers limited ACID guarantees (for example, single-record or single-partition transactions), with strong consistency.
Does FerretDB scale horizontally?
FerretDB does not scale horizontally; it runs on a single node, so you scale it up rather than out. It is comfortable at medium scale (≤ 10 TB).
How can I run FerretDB?
You can self-host it.
What is FerretDB best for?
FerretDB is a strong fit for existing deployments already running FerretDB 2.x and small apps such as LibreChat needing a MongoDB-compatible store on Postgres. Think twice for new projects (choose DocumentDB or MongoDB).
What are the best alternatives to FerretDB?
Common alternatives to FerretDB include DocumentDB (open-source, PostgreSQL-based); MongoDB; Percona Server for MongoDB; Azure DocumentDB; and PostgreSQL. The right choice depends on your workload, scale and hosting; WhichDB's smart match ranks them against your requirements.
Is FerretDB still maintained?
FerretDB is in maintenance mode. No release since v2.7.0 (Nov 2025), commits stalled in early 2026 and ferretdb.com lapsed, after MongoDB's 2025 patent suit. Consider DocumentDB (Linux Foundation) instead.
How popular is FerretDB?
FerretDB ranks #309 of 844 databases on the WhichDB Score (9.5/100), and #29 among document databases. The score combines public adoption signals such as package downloads, GitHub activity, job posts and developer discussion.