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FerretDB was founded to become the de-facto open-source substitute to MongoDB. FerretDB is an open-source proxy, converting the MongoDB 5.0+ wire protocol queries to SQL - using PostgreSQL or SQLite as a database engine.

flowchart LR
  A["Any application\nAny MongoDB driver"]

  A -- "MongoDB protocol\nBSON" --> F
  F -- "PostgreSQL protocol\nSQL" --> P
  F -. "SQLite library\nSQL" .-> S

Why do we need FerretDB?

MongoDB was originally an eye-opening technology for many of us developers, empowering us to build applications faster than using relational databases. In its early days, its ease-to-use and well-documented drivers made MongoDB one of the simplest database solutions available. However, as time passed, MongoDB abandoned its open-source roots; changing the license to SSPL - making it unusable for many open source and early-stage commercial projects.

Most MongoDB users do not require any advanced features offered by MongoDB; however, they need an easy-to-use open-source document database solution. Recognizing this, FerretDB is here to fill that gap.

Scope and current state

FerretDB is compatible with MongoDB drivers and popular MongoDB tools. It functions as a drop-in replacement for MongoDB 5.0+ in many cases. Features are constantly being added to further increase compatibility and performance.

We welcome all contributors. See our public roadmap, a list of known differences with MongoDB, and contributing guidelines.


Run this command to start FerretDB with PostgreSQL backend:

docker run -d --rm --name ferretdb -p 27017:27017

Alternatively, run this command to start FerretDB with SQLite backend:

docker run -d --rm --name ferretdb -p 27017:27017 -e FERRETDB_HANDLER=sqlite

This command will start a container with FerretDB, PostgreSQL/SQLite, and MongoDB Shell for quick testing and experiments. However, it is unsuitable for production use cases because it keeps all data inside and loses it on shutdown. See our Docker quickstart guide for instructions that don't have those problems.

With that container running, you can:

  • Connect to it with any MongoDB client application using MongoDB URI mongodb://
  • Connect to it using MongoDB Shell by just running mongosh. If you don't have it installed locally, you can run docker exec -it ferretdb mongosh.
  • For the PostgreSQL backend, connect to it by running docker exec -it ferretdb psql -U username ferretdb. FerretDB uses PostgreSQL schemas for MongoDB databases. So, if you created some collections in the test database using any MongoDB client, you can switch to it by running SET search_path = 'test'; query and see a list of PostgreSQL tables by running \d psql command.
  • For the SQLite backend, connect to it by running docker exec -it ferretdb sqlite3 /state/<database>.sqlite. So, if you created some collections in the test database using any MongoDB client, run docker exec -it ferretdb sqlite3 /state/test.sqlite and see a list of SQLite tables by running .tables command.

You can stop the container with docker stop ferretdb.

We also provide binaries and packages for various Linux distributions, as well as Go library package that embeds FerretDB into your application. See our documentation for more details.

Building and packaging


We strongly advise users not to build FerretDB themselves. Instead, use binaries, Docker images, or packages provided by us.

FerretDB could be built as any other Go program, but a few generated files and build tags could affect it. See there for more details.

Managed FerretDB at cloud providers



If you want to contact FerretDB Inc., please use this form.