InvoicePlane is a free and open source invoicing application. The project is the official successor and owner of the codebase of FusionInvoice version 1.x, which was written by Jesse Terry. FusionInvoice was an open source software before but was transformed into a commercial product with the release of version 2.x. Kovah, the InvoicePlane project leader, took over the codebase and restarted the project with a new name: InvoicePlane.