FerretDB review: an open-source MongoDB-compatible database built on PostgreSQL. Explore features, licensing, FerretDB Cloud pricing, and alternatives.
FerretDB is an open-source proxy that speaks the MongoDB wire protocol and translates queries into SQL run against a PostgreSQL-based backend, giving developers a MongoDB-compatible document database experience without MongoDB's Server Side Public License.
Founded in 2021 by former Percona team members Peter Farkas, Alexey Palazhchenko, and Peter Zaitsev, FerretDB is released under the Apache 2.0 license and, since version 2.0 in March 2025, runs on Microsoft's open-source DocumentDB PostgreSQL extension for significantly improved performance.
FerretDB acts as a drop-in replacement for MongoDB 5.0 and later, letting existing MongoDB drivers and tools connect without code changes while data is stored in PostgreSQL, and it can be deployed via Docker, Docker Compose, prebuilt Linux binaries, or embedded as a Go package.
Version 2.0 introduced Microsoft's DocumentDB PostgreSQL extension as the storage layer, claimed to deliver up to twenty times faster performance than the prior architecture along with new vector search and replication capabilities.
The core FerretDB software is completely free and open source under the Apache 2.0 license, with no cost to download, self-host, or embed it in an application.
FerretDB Cloud, a managed database-as-a-service launched in August 2025, offers Free, Pro, Enterprise, and Bring Your Own Account tiers, though specific dollar pricing for the paid tiers has not been published and access currently requires a waitlist on AWS.
Yes, the core FerretDB software is free and open source under the Apache 2.0 license; a separate paid managed service called FerretDB Cloud also exists but its dollar pricing has not been publicly disclosed.
FerretDB stores data in PostgreSQL, and since version 2.0 it uses Microsoft's open-source DocumentDB PostgreSQL extension for improved performance and features like vector search and replication.
FerretDB was created in response to MongoDB's move to the Server Side Public License in 2018, which the Open Source Initiative does not recognize as approved open source, giving developers a genuinely open-source, MongoDB-compatible alternative.
FerretDB is designed as a drop-in replacement for MongoDB 5.0 and later, translating the MongoDB wire protocol into SQL, so most existing MongoDB drivers and tools can connect with little to no code change.
FerretDB was founded in 2021 by Peter Farkas, Alexey Palazhchenko, and Peter Zaitsev, all previously associated with the open-source database company Percona.
SQLite was supported as a backend in the FerretDB 1.x release line, but it was dropped in version 2.0, which moved to PostgreSQL with the DocumentDB extension; the 1.x branch remains available on GitHub for legacy SQLite users.