🗄️ Databases
Free and open-source databases for apps, home servers and data analysis, graphical tools to work with them, and free places to learn SQL. See also my article Constructing a Database.
Open in the interactive Digital Resources
SQLite
sqlite.orgA complete SQL database in a single file, with no server to install. Built into browsers, phones and countless apps – the best place to start. Public domain.
PostgreSQL
postgresql.orgA powerful, reliable relational database server with a strong standards focus and many extensions. The most used database in the Stack Overflow Developer Survey 2025.
MariaDB
mariadb.orgA community-developed fork of MySQL by its original creators, largely compatible with it. Used by many self-hosted apps such as Nextcloud.
MySQL Community Edition
mysql.comThe free, open-source edition of one of the most widely used database servers on the web, now developed by Oracle.
DuckDB
duckdb.orgA fast analytical SQL database that runs inside your program or terminal and can query CSV, JSON and Parquet files directly. Great for data analysis.
Valkey
valkey.ioA fast in-memory key-value store for caches, queues and sessions, backed by the Linux Foundation and created from Redis after its 2024 licence change.
Redis Open Source
redis.ioThe original in-memory key-value store. It left open source in 2024 and returned with Redis 8 in 2025 under the AGPLv3 licence.
Apache CouchDB
couchdb.apache.orgA document database that stores JSON, talks plain HTTP and replicates between servers, phones and browsers – made for offline-first apps.
MongoDB Community Edition
mongodb.comA popular document database that stores flexible JSON-like records. Free to use under the SSPL licence, which is not an OSI-approved open-source licence.
pgvector
github.comAn extension that adds vector similarity search to PostgreSQL – the usual way to store embeddings for AI search over your own documents (RAG).
DBeaver Community
dbeaver.ioA universal database tool for PostgreSQL, MariaDB, MySQL, SQLite and many more – browse tables, edit data and run SQL queries.
DB Browser for SQLite
sqlitebrowser.orgA simple visual tool to create, open and edit SQLite database files, with a spreadsheet-like view of the data.
pgAdmin
pgadmin.orgThe best-known open-source administration and development tool for PostgreSQL, as a desktop or web application.
HeidiSQL
heidisql.comA lightweight, free database client for MariaDB, MySQL, SQL Server, PostgreSQL and SQLite – a long-time favourite on Windows, now also for Linux and macOS.
Beekeeper Studio Community
beekeeperstudio.ioA modern, easy-to-use SQL editor and database manager for many databases. The community edition is free and open source.
Adminer
adminer.orgComplete database management in a single PHP file – put it on a web server and manage MySQL, MariaDB, PostgreSQL or SQLite from the browser.
PostgreSQL Tutorial
postgresql.orgThe official introduction to PostgreSQL and SQL in the PostgreSQL documentation, from creating a database to transactions.
Use The Index, Luke
use-the-index-luke.comA free online book by Markus Winand about SQL indexes and performance, for PostgreSQL, MySQL, Oracle, SQL Server and Db2.
PostgreSQL Exercises
pgexercises.comPractise SQL step by step on one small example database – from simple queries to joins, aggregates and window functions.