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Open-Source Databases

The database layer stores your application's state — the part of the stack where 'sovereignty' becomes concrete: if you control where the data lives, everything else is negotiable.

13 providers2 European13 open source2 European countries

Why this layer matters for sovereignty

  • Data residency is a legal property of the database, not of the app: a US-cloud-hosted EU app still stores its data under US jurisdiction.

  • Open-source engines (PostgreSQL, MariaDB, SQLite) carry no license risk from vendor repricing — the recent wave of license changes in 'open-source' cloud products shows why that matters.

  • Managed European platforms give you database-as-a-service convenience with EEA-stored data and GDPR-native DPAs.

What to look for

  • Match the model to the access pattern: relational (PostgreSQL, MariaDB) for most workloads, document (MongoDB), time-series (InfluxDB, QuestDB), or embedded (SQLite, DuckDB) for analytical work on a single machine.

  • For managed: backups, point-in-time recovery, and PITR are worth more than a feature list.

  • For self-hosting: replication and failover tooling — the database is the one layer where manual ops hurt most.

  • Permissive licensing (PostgreSQL-style) if you might embed or distribute.

European & open-source database providers

Curated as part of the European Stack Builder. Badges reflect the organization's origin — EU, EEA, EFTA, and UK count as European.

Aiven

Aiven
aiven.io

FI

Managed open-source data platform providing hosted versions of popular databases

EuropeanOpen Source
DuckDB

DuckDB
duckdb.org

NL

In-process analytical database designed for high-performance workloads

EuropeanOpen Source
InfluxDB

InfluxDB
influxdata.com

Time-series database for high-volume metrics and real-time events

Open Source
libSQL

libSQL
libsql.org

Open-contribution fork of SQLite with enhanced features

Open Source
MariaDB

MariaDB
mariadb.org

Community-driven relational database

Open Source
MongoDB

MongoDB
mongodb.com

Popular document-oriented NoSQL database for flexible and scalable data storage

Open Source
MySQL

MySQL
mysql.com

World's most widely used open-source relational DBMS

Open Source
PostgreSQL

PostgreSQL
postgresql.org

Most advanced open-source relational database focussed on extensibility and standards

Open Source
QuestDB

QuestDB
questdb.io

High-performance time-series database for real-time analytics

Open Source
Redis

Redis
redis.io

Real-time data platform used as a cache, message broker, and in-memory database

Open Source
SQLite

SQLite
sqlite.org

Small, self-contained, and serverless SQL engine.

Open Source
Supabase

Supabase
supabase.com

Firebase alternative providing a full backend suite built on PostgreSQL

Open Source
Valkey

Valkey
valkey.io

Linux Foundation-governed fork of Redis maintaining a permissive license

Open Source

Frequently asked questions

Which open-source database should I use?

For most applications the answer is PostgreSQL: it is permissively licensed, ACID-compliant, handles relational and JSON workloads, and every European cloud platform offers a managed version. MariaDB/MySQL cover the same space with a different heritage, MongoDB suits document-shaped data, InfluxDB and QuestDB handle time-series, and SQLite or DuckDB run embedded without a server.

What is a managed database?

A managed database is operated by a platform provider: they run the servers, handle backups, updates, replication, and monitoring, and you consume it over the network. The sovereignty question is where that provider stores the data — a European platform keeps it inside the EEA under the GDPR.

Pick your Database

Compare these providers side by side and assemble your full sovereign stack.

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