FerretDB was founded in 2021, set out to develop an open source, MongoDB-compatible Document Database. Actually it’s based in USA (at Delaware). During last IT Press Tour #61, Peter Farkas (co-founder and company’s CEO) provides more information about the company and their product.

FerretDB is a truly Open Source MongoDB alternative, built on PostgreSQL and SQLite.

FerretDB allows you to use MongoDB drivers seamlessly with PostgreSQL as the database backend. Use all tools, drivers, UIs, and the same query language and stay Open Source.

But why do we need an alternative to MongoDB? Isn’t MongoDB also an Open Source produtct? Technically no more… it started as a full OpenSource software, but on 2018 they start using the SSPL (Server Side Public License) designed to ensure that companies that offer MongoDB’s database software as a service (DBaaS), contribute back to the Open Source community.

The SSPL is a copyleft license that put some limitation in the use cases: any organization that offers MongoDB as a service has to release the source code of the entire service under the SSPL as well. This is different from true Open Source licenses, which only require modifications to the original software to be released under the same license.

To compare FerretDB and MongoDB architecture and licensing:

WiredTiger was an acquisition of MongoDB in later 2014, and has become the default database storage engine technology since MongoDB 3.0. 

Note that MongoDB drivers are the main reason behind high adoption of MongoDB and are free to use under Apache 2.0.

FerretDB is a proxy that converts MongoDB 5.0+ wire protocol queries to SQL and uses PostgreSQL with DocumentDB extension as a database engine.

FerretDB is compatible with MongoDB drivers and can be used as a direct replacement for MongoDB 5.0+.

FerretDB 2.0 went in GA on March 5, 2025 and it’s fully ready for production!

This release is a result of a year-long collaboration: FerretDB worked together with Microsoft to combine the engine of Azure Cosmos DB for MongoDB (vCore) and FerretDB, releasing both under a fully open-source license.

Version 2.0 introduces transformative improvements in performance, compatibility, scalability, and flexibility. Key highlights include:

• Over 20x faster performance powered by Microsoft DocumentDB. Note that Azure Cosmos DB for MongoDB (vCore) is built on the same extension, enabling FerretDB and Cosmos DB users to move their workloads seamlessly between the two.
• Enhanced MongoDB compatibility for seamless application migration.
• Vector search support for AI-driven use cases.
• Replication support for high-availability: FerretDB uses PostgreSQL + DocumentDB extension as the database storage and currently supports replication using the Write-Ahead Logging (WAL) streaming method. 
• Enterprise-grade support and services.

Which is the market approach of FerredDB? Like other Open Source product, they provide a lot of services:

• Product Support: from product evaluation, production down situations, 24/7 Q&A, to complex technical troubleshooting.
• Product Development: is possible to ask to add custom features into FerretDB, to ensure that it integrates with your solutions.
• Training and Consulting