What is H2 Database used for?

H2 Database is a fast, embeddable SQL database written in pure Java, with JDBC access, in-memory or disk storage, encryption and a browser-based console. It is a good fit for fast in-memory databases for tests and embedded SQL storage in Java apps.

Is H2 Database open source?

Yes. H2 Database is open source under a custom licence. Its source code is on GitHub at h2database/h2database and is written mainly in Java.

Yes. H2 Database is open source, so the software itself is free to use under the terms of its own licence.

Can I self-host H2 Database?

Yes. H2 Database can be self-hosted on your own server or infrastructure; there is no official hosted version.

What are some alternatives to H2 Database?

Similar open-source tools in the Databases category include DuckDB, PostgreSQL and QuestDB. SaaS products in the same category include Amazon MemoryDB, Cloudflare D1 and Exasol.

Is H2 Database actively maintained?

Yes. The most recent commit to H2 Database was on 1 October 2026. The project has 4.6k stars on GitHub.

H2 Database: open-source databases

About H2 Database

H2 is a relational database management system written in Java. It can run embedded inside an application or as a standalone server, and databases can live on disk or purely in memory, which makes it popular for development, testing and small production uses where a full database server would be overkill.

Listed features include a JDBC API, transaction support with multi-version concurrency, a browser-based console application, encrypted databases and full-text search. It is pure Java with a small footprint, about 2.5 MB for the jar, and it also provides an ODBC driver. The project documents SQL commands, functions, aggregate and window functions and data types, and offers a tutorial, issue tracker and forum.

H2 is open source, with its license shown as 'Other' on GitHub, and is added to Java projects as a dependency, so no hosting is needed. It suits Java developers who want a lightweight database for unit tests, prototypes and embedded applications.

Key features

Embedded and server modes
In-memory or disk-based databases
JDBC API and ODBC driver
Transactions with multi-version concurrency
Browser-based console application
Encrypted databases and full-text search

Good fit for

→Fast in-memory databases for tests
→Embedded SQL storage in Java apps

Built with: Java
Tags: database; java; sql; jdbc; embedded-database; in-memory; rdbms

H2 Database: questions and answers

What is H2 Database used for?: H2 Database is a fast, embeddable SQL database written in pure Java, with JDBC access, in-memory or disk storage, encryption and a browser-based console. It is a good fit for fast in-memory databases for tests and embedded SQL storage in Java apps.
Is H2 Database open source?: Yes. H2 Database is open source under a custom licence. Its source code is on GitHub at h2database/h2database and is written mainly in Java.
Is H2 Database free?: Yes. H2 Database is open source, so the software itself is free to use under the terms of its own licence.
Can I self-host H2 Database?: Yes. H2 Database can be self-hosted on your own server or infrastructure; there is no official hosted version.
What are some alternatives to H2 Database?: Similar open-source tools in the Databases category include DuckDB, PostgreSQL and QuestDB. SaaS products in the same category include Amazon MemoryDB, Cloudflare D1 and Exasol.
Is H2 Database actively maintained?: Yes. The most recent commit to H2 Database was on 1 October 2026. The project has 4.6k stars on GitHub.