Perst is an open source, dual license, object-oriented embedded database system (ODBMS). It is available in one edition developed as an all-Java embedded database, and another implemented in C# (for Microsoft .NET Framework applications). Users can redistribute and/or modify Perst under the terms of the GNU General Public License version 3 (or earlier versions) as published by the Free Software Foundation. For projects that don’t fit under the GPL, a commercial license for Perst may be purchased.[01]