FerretDB vs MongoDB Community (self-hosted)
Both are alternatives to MongoDB Atlas. Here's how they stack up — verified facts, no spin.
Also searched as MongoDB Community (self-hosted) vs FerretDB — same comparison, one verdict.
FerretDB
MongoDB's wire protocol, speaking to Postgres underneath.
FerretDB implements the MongoDB wire protocol on top of Postgres, so an existing application keeps its drivers, its queries and its code while the data lives in an open relational database under a licence nobody will change. Apache-2.0, around 11k stars. It is the most surgical exit in this comparison: for the common case of a team using MongoDB as a straightforward document store, it is close to a drop-in. Compatibility is good rather than total — the exotic aggregation stages and MongoDB-specific features are where it stops.
MongoDB Community (self-hosted)
The same database, on your own servers, for the price of the servers.
The most overlooked option: run MongoDB yourself. It is the identical database engine, free of charge, and for the overwhelming majority of users the SSPL restriction is irrelevant — it only bites if you offer MongoDB itself as a service to third parties. Read the licence against your own situation rather than the argument about it. What you give up is Atlas: no managed backups, no automatic failover configuration, no Atlas Search, and you own upgrades and monitoring. What you keep is every query and every driver, unchanged.
Side by side
| FerretDB | MongoDB Community (self-hosted) | |
|---|---|---|
| Sovereignty Score | 95 | 70 |
| Open source | Yes | No |
| Self-hostable | Yes | Yes |
| Local-first | Yes | Yes |
| License | Apache-2.0 | SSPL (source-available, not OSI open source) |
| Pricing | Free and open source. You run it alongside your own Postgres. | Free to download and run. You pay for servers and the people who operate them. |
FerretDB edges it on the Sovereignty Score, but the right pick depends on the trade-offs below.
FerretDB
Strengths
- +Existing MongoDB drivers and queries keep working — minimal code change
- +Apache-2.0, with data resting in Postgres
- +Sidesteps the SSPL question entirely
- +Lets you consolidate onto one database engine
Trade-offs
- −Compatibility is good but not complete — test your aggregations
- −Extra layer between application and storage
- −Younger project with a smaller community
- −Not faster than MongoDB; this is about licence and consolidation
MongoDB Community (self-hosted)
Strengths
- +Identical engine — zero application changes
- +No cluster bill; a modest server handles a lot
- +Full control over version, configuration and data location
- +SSPL restrictions do not apply to ordinary internal use
Trade-offs
- −SSPL is not OSI-approved open source, and that matters to some procurement teams
- −You own replica sets, failover, backups and upgrades
- −No Atlas Search, Vector Search or Triggers
- −Operating MongoDB well across zones is a genuine specialism
More MongoDB Atlas head-to-heads
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Facts verified 2026-08-07. Licenses and pricing change — spotted something out of date? That's a correction we want.