HSQLDB is the leading SQL relational database engine written in Java. It has a JDBC driver and supports a rich subset of ANSI-92 SQL (BNF tree format) plus SQL 99 and 2003 enhancements. It offers a small (less than 100k in one version), fast database engine which offers both in-memory and disk-based tables. Embedded and server modes are available. Additionally, it includes tools such as a minimal web server, in-memory query and management tools (can be run as applets) and a number of demonstration examples.

The product is currently being used as a database and persistence engine in many Open Source Software projects and even in commercial projects and products. In it's current version it is extremely stable and reliable. It is best known for its small size, ability to execute completely in memory and its speed.

This feature-packed software is completely free under our licenses . Yes, that's right, completely free of cost or onerous restrictions! Java source code and extensive documentation always included!

Users please visit the Project Summary Page for more information and to submit Patches, Bugs, Feature Requests and communicate with the Project Team or view/browse/subscribe to one or more of our mailing lists.

Our group was formed in 2001 and has as its charter the continuation of Thomas Mueller's closed Hypersonic SQL Project. We have actively developed and released five new versions of the database since April 2001. The latest release version features a wide range of new functionality and code rewrite. The project enjoys an overall ranking of 84 among all SourceForege projects (85,000) with over 200,000 downloads.