Why not self-host MongoDB?

MongoDB Community is SSPL. That is not an OSI open-source license. FerretDB is Apache-2.0 on Postgres. Compatibility is good for many apps — test your queries before you cut over.

If you do not need a Mongo driver, skip the proxy. PocketBase is the c17 app database. This page is for teams stuck on a Mongo client.

Stacks / Backend

Medium

FerretDB + Postgres

Mongo-compatible documents on Postgres. FerretDB is Apache-2.0. MongoDB Community is SSPL — not OSI open source — so it is not the path.

The problem

MongoDB Atlas is a hosted cluster with a meter. MongoDB Community Server is SSPL, which OSI does not list as open source. FerretDB is Apache-2.0: it speaks the MongoDB 5.0+ wire protocol and stores data in PostgreSQL (DocumentDB extension). If you do not need the Mongo protocol, /stacks/go-pocketbase-htmx is the simpler app database.

Replaces

MongoDB Atlas

Replace MongoDB Atlas

Estimated SaaS saved

$2,400

per year, small team, before lock-in

Start on Railway

Go + PocketBase if you can skip the Mongo protocol

Sponsor this stack Tip jar

Placeholder: FerretDB + the project's Postgres/DocumentDB image, data on a volume. Apps that do not need Mongo talk should use /stacks/go-pocketbase-htmx instead.

The stack

FerretDB
Apache-2.0 MongoDB-compatible proxy on Postgres
PocketBase
Embedded SQLite app database if you do not need Mongo
Catalog entry →

Cost table

You stop paying	Typical / year	Self-host instead
MongoDB Atlas dedicated (small team)	$2,400	FerretDB + Postgres

Agent setup prompt

Replace MongoDB Atlas with FerretDB + PostgreSQL.

Do not install MongoDB Community and call it open source — it is SSPL.
- Follow FerretDB's production compose (FerretDB + the DocumentDB Postgres image). Persist Postgres on a volume.
- Point one existing Mongo driver at the new URI. Confirm a find and an insert.
- If the app can drop Mongo entirely, use /stacks/go-pocketbase-htmx instead.
- Write AGENT_PROMPT.md.

Also as markdown: /stacks/ferretdb-mongo.md

FAQ

Why not self-host MongoDB?: MongoDB Community is SSPL. That is not an OSI open-source license. FerretDB is Apache-2.0 on Postgres. Compatibility is good for many apps — test your queries before you cut over.
Why PocketBase then?: If you do not need a Mongo driver, skip the proxy. PocketBase is the c17 app database. This page is for teams stuck on a Mongo client.