HSQLDB has been constantly developed over 20 years and is used as a database and persistence engine in over 1700 Open Source Software projects and many commercial products. The latest versions are extremely stable and reliable. It is known for its small size, ability to execute completely or partly in memory, its flexibility and speed.
HSQLDB is completely free to use and distribute under our licenses, based on the standard BSD license and fully compatible with all major open source licenses.